
/^^ 



bureau of titandardft 


J 


Tfl 439 




.J6 




1921 




Copy 1 





PROGRESS REPORT 

OF THE 

JOINT COMMITTEE ON STANDARD SPECIFICATIONS 

FOR 
CONCRETE AND REINFORCED CONCRETE 



SUBMITTING 
TENTATIVE SPECIFICATIONS FOR CONCRETE AND 
REINFORCED CONCRETE 



Affiliated Committees 

OF THE 

American Society of Civil Engineers 
American Society for Testing Materials 
American Railway Engineering Association 
American Concrete Institute 
Portland Cement Association 



Submitted to Constituent Organizations 
June 4, 1921 



<^ 



A 2^ 






n 



PREFACE. 

The Joint Committee on Standard Specij&cations for Concrete 
and Reinforced Concrete consists of five representatives from each 
of the following: 

American Society of Civil Engineers, 

American Society for Testing Materials, 

American Railway Engineering Association, 

American Concrete Institute, 

Portland Cement ^Association. 

This Committee is the successor • of the Joint Committee on 
Concrete and Reinforced Concrete which was organized in Atlantic 
City, N. J., June 17, 1904, and was formed by the union of special 
committees appointed in 1903 and 1904 by the above-named organi- 
zations, except the American Concrete Institute which was added by 
invitation of the Joint Committee in 1915. The previous Committee 
presented progress reports in 1909 and 1912 and adopted a final 
report to its constituent organizations on July 1, 1916. It was the 
purpose of that Committee to prepare a Recommended Practice for 
Concrete and Reinforced Concrete. Its final report. stated: 

''The report is not a specification but may be used as a basis for 
specifications." 

The present Joint Committee is charged with the preparation of 
Specifications for Concrete and Reinforced Concrete and in preparing 
these specifications is using as a basis the report of the former Joint 
Committee with such modifications as are necessary to make its 
recommendations agree with current practice, and such new data as 
mark advances in the art. 

The initiative in bringing about the present Joint Committee 
was taken by the Committee on Reinforced Concrete of the American 
Society for Testing Materials on June 27, 1917, when the committee 
voted to request the Executive Committee of the Society to invite 
the Member-Societies of the previous Joint Committee to cooperate 
in the formation of a new Joint Committee. The Executive Com- 
mittee approved this request on April 25, 1919, and an invitation 
was issued to each of the above-named organizations by the Execu- 
tive Committee on behalf of the American Society for Testing 

(3) 



4 Progress Report of Joint Committee 

Materials, to appoint five members on a Joint Committee on Specifi- 
cations for Reinforced Concrete. The last of these organizations 
accepted the invitation on November 22, 1919. On January 21, 
1920, a call for an organizing meeting on February 11, 1920, was 
sent by the Executive Committee of that Society to each of the 
twenty-five representatives of cooperating organizations, together 
with a list of members of the Joint Committee, and an outline of 
organization that had been previously submitted by the American 
Society for Testing Materials to and approved by the cooperating 
organizations. 

The organizing meeting was held at the Engineers' Club, Phila- 
delphia, Pa., and was called to order by George S. Webster, then Vice- 
President of the American Society for Testing Materials, who explained 
that he had been directed by the Executive Committee of that 
Society to act as Temporary Chairman; he further stated that 
C. L. Warwick, Secretary-Treasurer of the Society, had been requested 
to act as Temporary Secretary until a formal organization of the 
Joint Committee had been effected. 

The personnel of the Joint Committee is as follows: 

American Society of Civil Engineers. 
Rudolph P. Miller, Chairman, 

Consulting Engineer, New York City. 

Resigned March 28, 1921. Succeeded as Chairman by 

W. A. Slater, Engineer -Physicist, 

Bureau of Standards, Washington, D. C. 
William K. Hatt, Professor of Civil Engineering, 

Purdue University, Lafayette, Ind. 
A. E. Lindau, General Manager of Sales, 

Corrugated Bar Company, Buffalo, N. Y. 
Sanford E. Thompson, Consulting Engineer, 

Boston, Mass. 

Appointed to fill vacancy, 

Franklin R. McMillan, 

628 Metropolitan Bank Building, Minneapolis, Minn. 

American Society for Testing Materials. 
Richard L. Humphrey, Chairman, 

Consulting Engineer, Philadelphia, Pa. 
Albert T. Goldbeck, Engineer of Tests, 

Bureau of Public Roads, Washington, D. C. 
Edward E. Hughes, Vice-President, 

Franklin Steel Works, Franklin, Pa. 
Henry H. Quimby, Chief Engineer, 

Department of City Transit, Philadelphia, Pa. 
Leon S. Moisseiff, Consulting Engineer, 

New York City. 



On Concrete and Reinforced Concrete. 5 

American Railway Engineering Association. 
J. J. Yates, Chairman, 

Bridge Engineer, Central Railroad of New Jersey, Jersey City, N, J. 
George E. Boyd, Division Engineer, 

Delaware, Lackawanna and Western Railroad Company, Buffalo, N. Y. 
Frederick E. Schall, Bridge Engineer, 

Lehigh Valley Railroad Company, Bethlehem, Pa. ' 

H. T. Welty, Engineer of Structures. 

New York Central Railroad, New York City. 
C. C. Westfall, Engineer of Bridges, 

Illinois Central Railroad Company, Chicago, 111, 

American Concrete Institute. 
S. C. Hollister, Chairman. 

Consulting Engineer, Philadelphia, Pa. 
Robert W. Lesley, Past-President, Association of American Portland 
Cement Manufacturers, 

Philadelphia, Pa. 
Arthur R. Lord, President, 

Lord Engineering Company, Chicago, 111. 
Egbert J. Moore, Vice-President, 

Turner Construction Company, New York City. 
Leonard C. Wason, President, 

Aberthaw Construction Company, Boston, Mass. 

Resigned October 19, 1920. Succeeded by 

Angus B. MacMillan, Chief Engineer, 

Aberthaw Construction Company, Boston, Mass. 

Portland Cement Association. 

Frederick W. Kelley, Chairman, 

President, Helderberg Cement Company, Albany, N. Y. 
Duff A. Abrams, Professor in Charge, 

Structural Materials Research Laboratory, Lewis Institute, Chicago, 111. 
Ernest Ashton, Chemical Engineer, 

Lehigh Portland Cement Company, Allentown, Pa. 
Edward D. Boyer, Cement Expert, 

Atlas Portland Cement Company, New York City. 
J. H. Libberton, Manager Service Bureau, 

Universal Portland Cement Company, Chicago. 111. 

Resigned January 1, 1921. Succeeded by 

J. E. Freeman, Manager, Structural Bureau, 
Portland Cement Association, Chicago, 111. 

The Committee perfected a permanent organization on February 
11, 1920, under the title ''Joint Committee on Standard Specifications 
for Concrete and Reinforced Concrete" with the following officers: 

Chairman J Richard L. Humphrey, Philadelphia, Pa., 

Vice-Chair man, J. J. Yates, Jersey City, N. J., 

Secretary-Treasurer, Duff A. Abrams, Chicago, 111.", 



Progress Report of Joint Committee 



and an Executive Committee consisting of these officers, and Rudolph 
P. Miller,^ New York City, and S. C. HoUister, Philadelphia. 

The Committee adopted Rules of Organization and apportioned 
the work of preparing a tentative draft of the specifications among 
sub-committees, the present personnel of which is given below: 



Materials {other than Reinforcing). 2. 
Albert T. Goldbeck, Chairman 
Duff A. Abrams 
J. E. Freeman^ 
Sanford E. Thompson 
J. J. Yates 



Metal Reinforcement. 
J. J. Yates, Chairman 
Duff A. Abrams 
William K. Hatt 
Edward E. Hughes 
A. E. Lindau 



Proportioning and Mixing. 
W. A. Slater, Chairman 
Duff A. Abrams 
Ernest Ashton 
George E. Boyd 
Henry H. Quimby 



4. Forms and Placing. 

George E. Boyd, Chairman 
Edward D. Boyer 
Angus B. MacMillan3 
Egbert J. Moore 
Frederick E. Schall 



5. Design. 

S. C. Hollister, Chairman 
William K. Hatt 
A. E. Lindau 
Arthur R. Lord 
Franklin R. McMillan 
Egbert J. Moore 
W. A. Slater 
H. T. Welty 



Details of Construction and Fire- 
proofing. 
Franklin R. McMillan,'* Chairman 
William K. Hatt 
Arthur R. Lord 
Leon S. Moisseiff 
C. C. Westfall 



7. Waterproofing and Protective 
Treatment. 
Frederick W. Kelley, Chairman 
Albert T. Goldbeck 
S. C. Hollister 
Robert W. Lesley 
C. C. Westfall 



Surface Finish. 

Henry H. Quimby, Chairman 
Edward D. Boyer 
J. E. Freeman^ 
Angus B. MacMillans 
H. T,. Welty 



9. Form of Specification. 



Richard L. Humphrey, Chairman 
Duff A. Abrams, Secretary 
George E. Boyd 
Albert T. Goldbeck 
S. C. Hollister 



^ Succeeded by W. A. Slater, May 25, 1921. 
2 Succeeded J. H. Libberton, January 1, 1921. 
> Succeeded Leonard C. Wason. October 19, 1920. 
'Succeeded Rudolph P. Miller, May 25. 1921. 



Frederick V/. Kelley 
Franklin R. McMillan* 
Henry H. Quimby 
W. A. Slater 
J. J. Yates 



On Concrete and Reinforced Concrete. 7 

The Joint Committee held the following meetings: 
Organization meeting, Philadelphia, February 11, 1920. 
Second meeting, Asbury Park, N. J., June 23 and 24, 1920. 
Third meeting, New York City, October 26, 27 and 28, 1920. 
Fourth meeting. New York City, December 15, 16 and 17, 1920. 
Fifth meeting. New York City, March 2, 3 and 4, 1921. 
Sixth meeting, New York City, April 13, 14 and 15, 1921. 

At these meetings the Committee considered the reports of its 
sub-committees which were edited by the Sub-Committee on Form 
and incorporated in the Tentative Specifications for Concrete and 
Reinforced Concrete herewith submitted. 

The Rules of Organization of the Joint Committee which were 
submitted to, and approved by, each of its constituent organizations, 
provide that, 

"The initial report of the Joint Committee shall be con- 
sidered by each of the five organizations as a tentative report 
submitted for criticism and discussion limited to not less than 
six months nor more than one year. Such discussions shall 
then be referred to the Joint Committee for consideration in 
revising its report." (Article IX, Section 2.) 

The Joint Committee, in submitting these Tentative Specifica- 
tions for Concrete and Reinforced Concrete in accordance with the 
above requirement, wishes it clearly understood that it reserves the 
right to make such changes as may be found desirable, after a further 
study of the available data. While not prepared to submit a final 
report at this time the Committee is of the opinion that the specifi- 
cations are in such shape as to make it desirable to issue them tenta- 
tively for the purpose of facilitating the final submission of Standard 
Specifications for Concrete and Reinforced Concrete. 

The Joint Committee earnestly requests that every facihty be 
provided by its constituent organizations for the fullest considera- 
tion of these Tentative Specifications in order that it may be in a 
position, as a result of their thorough discussion, to reflect in the 
final specifications the best current practice. 

The Joint Committee further calls attention to the fact that it 
has undertaken to prepare specifications covering the fundamentals 
to be observed in the general use of concrete and reinforced concrete; 
no attempt has been made to cover the details involved in the use of 
these materials in special structures. While the sections relating to 
design deal primarily with buikling construction, nevertheless the 
principles involved are in general applicable to structures of other 



8 



Progress Report of Joint Committee. 



types. It is expected that in using these specifications the necessary 
supplemental requirements will be added covering details. 



This report has been submitted to letter ballot of the committee 
which consists of 25 members, representing five societies, all of whom 
have voted affirmatively. 

Respectfully submitted, 

Richard L. Humphrey, Chairman. 
J. J. Yates, V ice-Chairman. Durr A. Abrams, Secretary-Treasurer. 



Ernest Ashton, 
George E. Boyd, 
Edward D. Boyer, 
J. E. Freeman, 
Albert T. Goldbeck, 
William K. Hatt, 

S. C. HOLLISTER, 

Edward E. Hughes, 
Frederick W. Kelley, 
Robert W. Lesley, 
A. E. Lindau, 



Arthur R. Lord, 
Angus B. Mac Millan, 
Franklin R. McMillan, 
Leon S. Moisseiff, 
Egbert J. Moore, 
Henry H. Qiumby, 
Frederick E. Schall, 
W. A. Slater, 
Sanford E. Thompson, 
H. T. Welty, 
C. C. Westfall. 



TABLE OF CONTENTS. 

Section. Page. 

I. General Instructions • 1 II 

II. Definitions 2 1 1 14 

III. Quality of Concrete 3-5 15 

IV. Materials 

A . Portland Cement 6 15 

B. Fine Aggregate 7-12 15-16 

C. Coarse Aggregate 13-15 16 17 

D. Rubble and Cyclopean Aggregate 16-17 17 

E. Storage of Aggregate 18 17 

F. Water 19 17 

G. Metal Reinforcement 20-25 1 7-18 

V. Proportioning and Mixing Concrete 

A . Proportioning 26-28 

B. Consistency 29 

C. Mixing 30-33 

VI. Depositing Concrete 

A . Depositing in Air 34-43 

B. Rubble and Cyclopean Concrete 44-45 

C. Depositing under Water 46-5 1 

VII. Forms 52-58 

VIII. Details of Construction 

A. Metal Reinforcement 59-65 

B. Concrete Covering over Metal 66-68 

C. Joints 69-77 

IX. Waterproofing and Protective Treatment 

A . Waterproofing 78-8 1 

B. Oilproofing 82 

C. Concrete in Sea Water 83-86 

D. Concrete in Alkali Soils or Water 87-91 

X. Surface Finish 92-104 

XI. Design 

A. General Assumptions 105 32-33 

B. Flexure of Rectangular Reinforced Concrete Beams 

and Slabs 106-1 1 1 

C. Flexure of Reinforced Concrete T-Beams 112-1 19 

D. Diagonal Tension and Shear 

a. Formulas and Notation 120-121 

b. Beams without Web Reinforcement 122-123 

c. Beams with Web Reinforcement 124-135 

d. Flat Slabs 136 

e. Footings 137-139 

E. Bond 140-144 

F. Flat Slabs 145-162 

G. Reinforced Concrete Columns 163-173 

H. Footings 174-191 

(9) 



19- 


-20 




20 




21 


21- 


-23 




23 


23- 


-24 


24- 


-25 


25- 


-26 


26- 


-27 


27- 


-28 




28 




29 




29 


29- 


-30 


30- 


-32 



33- 


-37 


37- 


-39 


39- 


-40 




40 


40- 


-43 


43- 


-44 




44 


44- 


-45 


45- 


-50 


50- 


-53 


53- 


-56 



22 


18 


29 


20 


47 


46 



10 Report of Joint Committee. 

• Section. Page. 

/. Retaining Walls. 192-195 57-58 

/. Floor Slabs Supported on Four Sides 58 

K. Shrinkage and Temperature Stresses 58 

L. Summary of Working Stresses 196-208 58-59 

List of Tables. 

I. Size and Areas of Reinforcement Bars 

II. Workability of Concrete 

III. Moments to be Used in Design of Flat Slabs 

IV. Proportions for Concrete of Given Compressive Strength at 

28 Days ... 60-64 

* List of Appendices. 

The specifications and methods of test given in Appendices 3 to 15, 
inclusive, form a part of the Tentative Specifications for Concrete and 
Reinforced Concrete.^ 

Page. 

1. Standard Notation 65-67 

2. Figures 68-73 

3. Standard Specifications and Tests for Portland Cement (C 9 - 21)^ 

4. Standard Specifications for Billet-Steel Concrete Reinforcement Bars 

(A 15-14)2 

5. Standard Specifications for Rail-Steel Concrete Reinforcement Bars (A 

16 - 14)2 _ 

6. Standard Specifications for Structural Steel for Bridges (A 7 - 21)^ 

7. Standard Specifications for Structural Steel for Buildings (A 9 - 21)^ 

8. Tentative Specifications for Cold- Drawn Steel Wire for Concrete Re- 

inforcement (A 82 - 21 T)3 

9. Tentative Method of Test for Sieve Analysis of Aggregates for Con- 

crete (C 41 - 21 T)3 

10. Standard Method of Test for Quantity of Clay and Silt in Sand for High- 

way Construction (D 74 - 21)2 

1 1 . Tentative Method of Test for Organic Impurities in Sands for Con- 

crete (C 40-21 T).3 

12. Tentative Specifications for Workability of Concrete for Concrete Pave- 

ments (D 62 - 20 T)3. 

13. Tentative Methods of Making Compression Tests of Concrete (C 39 - 

21 T)=' 

14. Standard Methods of Making and Storing Specimens of Concrete in 

the Field (C 31 - 21)^ 

15. Standard Specifications for Cast- Iron Pipe and Special Castings (A 

44 - 04)2 



1 These specifications and methods of test are those of the American Society for Testing 
Materials, either in their present form as adopted by the Society or in the form in which the 
respective committees of the Society will recommend them for action at the annual meeting of 
the Society, June 21-24, 1921. 

2 American Society for Testing Materials, 1921 Book of A. S. T. M. Standards. 

3 American Society for Testing Materials, Proceedings, Vol. XXI, Part I (1921). 



TENTATIVE SPECIFICATIONS 

FOR 

CONCRETE AND REINFORCED CONCRETE. 

I. GENERAL INSTRUCTIONS. 
1. These specilications are not complete; they cover the general Genera 



conditions affecting the use of concrete and reinforced concrete. 
To complete them it will be necessary for the engineer to 

(a) Provide the detail specifications covering the work in par- 
ticular in which the concrete and reinforced concrete are to be used; 

(b) Insert in Section 4 the strengths required for the several 
classes of concrete specified, based either upon preHminary tests or 
upon the values given in Table IV; 

(c) Insert in Section 14 the sizes of aggregates required; 

{d) Strike out one of the titles of the specifications in Section 20; 

(e) Strike out one of the titles of the specifications in Section 24; 

(f) Strike out one of the words "volume" or ''weight'' in Sec- 
tion 27; 

(g) Strike out two of the three Sections 28 and fill in the neces- 
sary blanks for the proportions; 

(h) Insert in Section 29 the slumps required; 
(i) Strike out the method or methods inapplicable to the work, 
in Section 50; 

(j) Strike out one of the two Sections 97. 

II. DEFINITIONS. 

2. The following definitions give the meaning of certain terms Definitiors 
as used in these specifications: 

Acid Proofing. — Treatment of a concrete surface to resist the 
action of acid solutions. 

Aggregate. — Inert material which is mixed with Portland cement 
and water to produce concrete; in general aggregate consists of sand, 
pebbles, gravel, crushed stone or gravel, or similar materials. (See 
Fine Aggregate, Coarse Aggregate.) 

Approved. — Meeting the approval of, or specifically authorized by, 
the Engineer. 

Buttressed Retaining Wall. — A reinforced concrete wall having a 
vertical stem and a horizontal base, with brackets on the side opposite 
the pressure face uniting the vertical section with the toe of the base. 

(11) 



12 Progress Report or Joint Committee 

Cantilever Retaining Wall. — A reinforced concrete wall having a 
vertical stem and a horizontal base, each of which resists by canti- 
lever action the pressure to which it is subjected. 

Cellular Retaining Wall. — ^A reinforced concrete wall with a 
horizontal base, longitudinal vertical sections, and a series of trans- 
verse walls, dividing the space between the longitudinal walls into 
cells which are filled with earth, or other suitable material. If the 
top of the cells is covered by a floor slab, the front longitudinal 
wall and the filling may be omitted. 

Coarse Aggregate. — Aggregate retained on a No. 4 sieve and of a 
maximum size generally not larger than 3 in. (See Aggregate, Fine 
Aggregate) 

Column. — A vertical compression member whose length exceeds 
three times its least horizontal dimension. 

Column Capital. — An enlargement of the upper end of a reinforced 
concrete column built monolithic with the column and flat slab to 
increase the moment of inertia of the column and the shearing resist- 
ance of the slab at sections where high bending moment or high shear 
may occur. 

Column Strip. — A portion of a panel of a flat slab which has a 
uniform width equal to one-fourth of the panel length on a line per- 
pendicular to the direction of the strip, and whose outer edge lies on 
the edge of the panel. (See Middle Strip) 

Concrete. — A mixture of Portland cement, fme aggregate, coarse 
aggregate and water. (See Mortar) 

Consistency. — ^A general term used to designate the relative 
plasticity of freshly mixed mortar and concrete. 

Counterforted Retaining Wall. — A reinforced concrete wall having 
a vertical stem and a horizontal base with brackets on the pressure 
face uniting the vertical section with the heel of the base. 

Crusher-Run Stone. — Unscreened crushed stone. (See Stone 
Screenings. 

Cyclopean Concrete. — Concrete in which stones larger than one- 
man size are individually embedded. 

Dead Load.— The weight of the structure plus fixed loads and 
forces. 

Deformed Bar. — Reinforcement bar with shoulders, lugs or pro- 
jections formed integrally from the body of the bar during roUing. 

Diagonal Direction. — A direction parallel or approximately 
parallel to the diagonal of the panel. 

Dropped Panel. — The structural portion of a flat slab which is 
thickened throughout an area surrounding the column capital. 



On Concrete .\nd Reinforced Concrete. 13 

Elective Area of Concrete. — The area of a section of the concrete 
which Hes between the tension reinforcement and the compression 
surface of the beam or slab. 

Elective Area of Reinforcement. — The area obtained by multi- 
plying the right cross-sectional area of the metal reinforcement by 
the cosine of the angle between the direction of the reinforcement bars 
or wires, and the direction for which the effec iveness of the reinforce- 
ment is to be determined. 

Engineer. — The engineer in responsible charge of design and 
construction. 

Fine Aggregate. — Aggregate passing through a No. 4 sieve. (See 
Aggregate, Coarse Aggregate) 

Flat Slab.— A flat concrete floor or roof plate having reinforcement 
bars extending in two or more directions and having no beams or 
girders to canry the load to the supporting columns. 

Footing. — A structural unit used to distribute wall or column 
loads to the supporting material, either directly or through piles. 

Gravel. — Loose material containing particles larger than sand, 
resulting from natural crushing and erosion of rocks. (See Sand.) 

Laitance. — The extremely fine particles which separate from 
freshly deposited mortar or concrete and collect on the top surface. 

Live Load. — Loads and forces which are variable. 

Membrane Waterproofing. — A coating reinforced by fabric, felt, 
or similar toughening material applied to structures to prevent con- 
tact of moisture. 

Middle Strip. — The portion of a panel of a flat slab which extends 
in a direction parallel to a side of the panel, whose width is one-half 
the panel length on a fine at right angles to the direction of the strip 
and whose center line Hes on the center line of the panel. (See 
Column Strip.) 

Mortar. — A mixture of Portland cement, fine aggregate and 
water. (See Concrete) 

Negative Reinforcement. — Reinforcement so placed as to take 
stress due to negative bending moment. 

Oilproofing. — Treatment of a concrete surface to resist the action 
of mineral, animal, or vegetable oils. 

One-Man Stone. — Stone larger than coarse aggregate and not 
exceeding 100 lb. in weight. (See Rubble Concrete) 

Panel Length. — The distance between centers of two columns of 
a panel, in either rectangular direction. 

Pedestal or Pier.-- A vertical compression member whose length 
does not exceed three times its least horizontal dimension. 



14 Progress Report of Joint Committee 

Pedestal Footing. — A member supporting a column, in which the 
projection from the face of the column on all sides is less than one- 
half the depth. 

Plain Concrete. — Concrete without metal reinforcement. 

Positive Reinforcement.— Remiorcement so placed as to take 
stress due to positive bending moment. 

Portland Cement. — The product obtained by finely pulverizing 
clinker produced by calcining to incipient fusion an intimate and 
properly proportioned mixture of argillaceous and calcareous materials, 
with no additions subsequent to calcination excepting water and 
calcined or uncalcined gypsum. 

Principal Design Section. — The vertical sections in a fiat slab on 
which the moments in the rectangular directions are critical. (See 
Section 146.) 

Ratio of Reinforcement. — The ratio of the effective area of the 
reinforcement cut by a section of a beam or slab to the effective area 
of the concrete cut by that section. 

Rectangidar Direction. — A direction parallel to a side of the panel. 

Reinforced Concrete. — Concrete in which metal is embedded in 
such a manner that the two materials act together in resisting stress. 

Rubble Aggregate. — Stone or gravel larger than coarse aggregate 
and not larger than one-man stone (See One- Man Stone.) 

Rubble Concrete. — Concrete in which pieces of rubble aggregate 
are individually embedded. (See Rubble Aggregate) 

Sand. — Loose material consisting of small grains (commonly 
quartz) resulting from the natural disintegration of rocks. (See 
Gravel) 

Screen. — A metal plate with closely spaced circular perforations. 
(See Sieve) 

Sieve. — Woven wire cloth with square openings. (See Screen) 

Slump. — The shortening of a standard test mass of concrete 
used as a measure of workability. 

Standard Sand. — Natural sand mined at Ottawa, 111., screened 
to pass a No. 20 sieve and retained on a No. 30 sieve, used as the 
fine aggregate in standard strength tests of Portland cement. (See 
Appendix 3 for Specifications.) 

Stone Screenings.—Un^QX&Qnedi crushed stone passing through a 
No. 4 sieve. (See Crusher-Run Stone) 

Tremie.—A w^ater-tight pipe of suitable dimensions, generally 
used in a vertical position, for depositing concrete under water. 

Wall Beam. — A reinforced concrete beam which extends from 
column to column along the outer edge of a wall panel. 



ns. 



On Concrete and Reinforced Concrete. 15 

III. QUALITY OF CONCRETE. 

3. The quality of concrete shall be expressed in terms of work- Quality, 
abihty as determined by the slump test and of the compressive 
strength at 28 days as determined by concrete tests of the materials 
to be used as specified in Section 28. The proportions required to 
produce concrete ha\dng the strength specified in Section 4 shall be 
determined in advance of the mixing of the concrete. 

4. The concrete shall develop under the conditions specified in strength. 
Section 3, for the various parts of the work, the following strengths^: 

lb. per sq. in. 

lb. per sq. in. 

lb. per sq. in. 

lb. per sq. in. 

5. Field concrete test specimens shall be made, stored and Tests of 
tested in accordance with the Standard Methods of IMaking and gp^edme 
Storing Specimens of Concrete in the Field (Serial Designation: 
C 31-21) of the American Society for Testing Materials. (Appendix 14.) 

IV. MATERIALS. 

A. Portland Cefitent. 

6. Portland cement shall conform to the Standard Specifications Portland 
and Tests for Portland Cement (Serial Designation: C 9-21) of the ®"^®° * 
American Society for Testing Materials^ (Appendix 3) and subse- 
quent revisions thereof. 

B. Fine Aggregate. 

7. Fine aggregate shall consist of sand, stone screenings or other General 
inert materials with similar characteristics, or a combination thereof, ®^^"'®™®° ^ 
having clean, hard, strong, durable, uncoated grains and free from 
injurious amounts of dust, lumps, soft or flaky particles, shale, alkah, 

organic matter, loam or other deleterious substances. 

8. Fine aggregate shall range in size from fine to coarse, preferably Grading, 
within the following limits: 

Passing through No. 4 sieve not less than 95 per cent 

Passing through No. 50 sieve not more than 30 " 

Weight removed by decantation " " " 3 " 

1 The engineer should insert the strengths required for the several classes of concrete specified, 
based either upon preliminary' tests or upon the values given in Table IV. 

- These specifications are also a standard of the following organizations: American Engineeiing 
Standards Committee, United States Government, American Railway Engineering Association, 
American Concrete Institute, and the Portland Cement Association. 



16 



Progress Report of Joint Committee 



9. The sieves and method of making sieve analysis shall conform 
to the Tentative Method of Test for Sieve Analysis of Aggregates for 
Concrete (Serial Designation: C 41-21 T) of the American Society for 
Testing Materials. (Appendix 9.) 

10. The decantation test shall be made in accordance with 
the Standard Method of Test for Quantity of Clay and Silt in 
Sand for Highway Construction (Serial Designation: D 74-21) of 
the American Society for Testing Materials. (Appendix 10.) 

11. Fine aggregate shall preferably be of such a quality that 
mortar briquettes, cylinders or prisms, consisting of one part by 
weight of Portland cement and three parts by weight of fine aggregate,' 
mixed and tested in accordance with the methods described in the 
Standard Specifications and Tests for Portland Cement (Appendix 3) 
will show a tensile or compressive strength at ages of 7 and 28 days 
not less than that of 1 : 3 standard Ottawa sand mortar of the same 
plasticity made with the same cement. However, fine aggregate 
w^hich fails to meet this requirement may be used, provided the pro- 
portions of cement, fine aggregate, coarse aggregate and water are 
such as to produce concrete of the strength specified. ^ Concrete 
tests shall be made in accordance with the Tentative Methods of 
Making Compression Tests of Concrete (Serial Designation: C 
39-21 T) of the American Society for Testing Materials. (Appen- 
dix 13.) 

12. Natural sand which shows a color darker than the standard 
color when tested in accordance with the Tentative Method of Test 
for Organic Impurities in Sands for Concrete (Serial Designation: 
C 40-21 T) of the American Society for Testing Materials (Appendix 
1 1) shall not be used, unless the concrete made with the materials 
and in the proportions to be used on the work is shown by tests to 
be of the required strength. 



C. Coarse Aggregate. 

General 13. Coarse aggregate shall consist of crushed stone, gravel, or 

Requirements, other approved inert materials with similar characteristics, or com- 
binations thereof, having clean, hard, strong, durable, uncoated 
particles free from injurious amounts of soft, friable, thin, elongated 
or laminated pieces, alkali, organic or other deleterious matter. 



1 In testing aggregate, care should be exercised to avoid the removal of any coating on the grains 
which may affect the strength. Natural sand should not be dried before being made into mortar, but 
should contain natural moisture. The quantity of water contained may be determined on a separate 
sample and the weight of the sand used in the test corrected for the moisture content. 

2 Table IV furnishes a guide in determining the proportions of materials required to produce a 
concrete of a given strength, using aggregates of various sizes and concrete of different consistencies. 



On Concrete and Reinforced Concrete. 



17 



14. Coarse aggregate shall range in size from line to coarse within Grading, 
the following limits^ : 

Passing — '^ in, vSieve (maximum size) not more than 95 ])er cent. 

Passing — ^ in. '* (intermediate size) .... — '^ to — '^ " 

Passing No. 4 " not more than 15 , " 

Passing No. S " " " " 5 

15. The test for size and grading of aggregate shall be made in Sieve Sizes, 
accordance with the Tentative Method of Test for Sieve Analysis of 
Aggregates for Concrete. (Appendix 9.) 

D. Rubble and Cyclopean Aggregate. Rubble 

16. Rubble aggregate shall consist of clean, hard, durable stone Aggregate. 
larger than coarse aggregate and not larger than one-man stone. Cyclopean 

17. Cyclopean aggregate shall consist of clean, hard, durable stone, Aggregate. 

free from fissures and planes of cleavage and larger than one-man 

stone. 

E. Storage of Aggregate. Aggregate 

18. Aggregate shall be so stored on platforms or otherwise as to s*°^^se. 
avoid the inclusion of foreign materials. Before using, frost, ice and 
lumps of frozen materials shall be removed. 



F. Water. 

19. Water for concrete shall be clean and free from oil, acid, 
alkali, organic matter, or other deleterious substance. 

G. Metal Reinforcement. 

20. Metal reinforcement shall be of a quality and character 
meeting the requirements of the Standard Specifications^ for Billet- 
Steel Concrete Reinforcement Bar^ (Serial Designation: A 15-14) of 
the American Society for Testing Materials (Appendix 4), Standard 

1 Where several suitable aggregates are available, a thorough investigation of the relative economy 
of each for producing concrete of the desired strength is advisable, especiallj^ for work of considerable 
magnitude. 

a The engineer should insert in these blanks the sizes of aggregates required. The size and grading 
to be used will be governed by local conditions. The limitation on size and grading is intended to secure 
uniformity of aggregate. The following table indicates desirable gradings for coarse aggregate for 
certain maximum sizes: 



General 
Requirements. 



Quality. 



Maximiim 

Size of 
Aggregate. 


Per Cent by Weight Passing 

Through Standard Sieves 

with Square Openings. 


Per Cent 
not mc 

No. 4 
Sieve. 


Passing, 
re than 


in. 


.3 in. 


2 in. 


I2 in. 


1 in. 


iin. 


No. 8 

Sieve. 


3 


100 
... 

... 


100 

... 


40 - 7.5 
100 


... 
40 - 7.5 

100 


40-75 
100 


15 
15 
15 

1- 
1., 




2 

l| 


5 


1 


. 


3 

4 


■' 



See footnote 1. 



18. 



18 



PtioGJiESS Report of Joint Committee 



Wire. 



Standard 
Sizes of 
Bars. 



Specifications^ for Rail-Steel Concrete Reinforcement Bars (Serial 
Designation: A 16-14) of the American Society for Testing Materials 
(Appendix 5), except that the provision for machining deformed bars 
before testing shall be eliminated. 

2 1 . Wire for concrete reinforcement shall conform to the require- 
ments of the Tentative Specifications for Cold-Drawn Steel Wire for 
Concrete Reinforcement (Serial Designation: A 82-21 T) of the 
American Society for Testing Materials. (Appendix 8.) 

22. Reinforcement bars shall conform to the areas and equivalent 
sizes shown in Table I. 



Table I. — Sizes and Areas of Reinforcement Bars. 



Deformed 
Bars. 



Structural 
Shapes. 



Cast Iron. 





Size of Bar, 
in. 


Area. 


sq 


in. 




r.ound. 


Square. 


f 


0.110 
0.19G 
0.307 
0.443 
0.601 
0.785 






i 


250 


i. 




f 




7 




1 


1.000 


1| 


1 266 


li 


1 563 







The areas of deformed bars shall be determined by the minimum 
cross-section thereof. 

23. An approved deformed bar shall be one that will develop a 
bond strength at least 25 per cent greater than that of a plain round 
bar of equivalent cross-sectional area.^ 

24. Structural steel shapes used for reinforcement shall conform 
to the requirements of the Standard Specifications^ for Structural 
Steel for Bridges (Serial Designation: A 7-21) of the American 
Society for Testing Materials (Appendix 6), Standard Specifications^ 
for Structural Steel for Buildings (Serial Designation: A 9-21) of the 
American Society for Testing Materials. (Appendix 7.) 

25. The quality of cast iron used in composite columns shall 
conform to the requirements of the Standard Specifications for 
Cast-iron Pipe and Special Castings (Serial Designation: A 44-04) 
of the American Society for Testing Materials. (Appendix 15.) 

1 The engineer should strike out one of these titles. The Committee recommends as preferred 
material for reinforcement that meeting the requirements of the Standard Specifications for Billet-Steel 
Concrete Reinforcement Bars of intermediate grade (except as noted under Section 20) , made by the 
open-hearth process. 

2 The Committee has under consideration a specification for deformed bars but is not prepared at 
this time to make more definite recommendations. 

^ The engineer should strike out one of these titles. 



On Concrete and Reineorced Concrete. 19 

V. PROPORTIONING AND MIXING CONCRETE. 
A . Proportioning. 

26. The unit of measure shall be the cubic foot. Ninety-four Unit of 
pounds (one bag or J bbl.) of Portland cement shall be considered as ^®^^"^®- 
one cubic fool.. 

27. Each of the constituent materials shall be measured separately Method of 
by volume^ weight.' The method of measurement shall be such as ^®*suring. 
to secure the specified proportions in each batch. If volume measure- 
ment is used, the fine aggregate and the coarse aggregate shall be 
measured loose as thrown into the measuring device. The water 

shall be measured by an automatic device that will insure the same 
quantity in successive batches. 

28.2 The proportions of cement, water and aggregate shall be Proportions, 
such as to produce concrete of the strength and quality specified in 
Sections 3 and 4. The proportions shall be 1 part of Portland cement, 
— " parts of fine aggregate, and — "^ parts of coarse aggregate as deter- 
mined by the engineer from concrete tests of the materials to be 
used. The tests shall be made in accordance with the Tentative 
Methods of Making Compression Tests of Concrete. (Appendix 13.) 
The quantity of water used shall be such as to produce concrete of 
the consistency required by the particular class of work and shall be 
as specified in Section 29. In case the grading of the supply of 
available aggregate varies from that upon which the proportions were 
based, such aggregate may be used, provided the new proportions, 
as determined by the engineer, are such as to produce concrete of the 
required strength and quality. 

28.2 The contractor shall use materials, so proportioned andmixed, Proportions. 
as to produce concrete of the required workability and strength.'' 
Frequent compression tests of the concrete used in the work will be 
made by the engineer, and in case of failure to meet the specified 
strength, the contractor shall make such changes in the materials, 
proportions, or mixing, as may be necessary to secure concrete of the 
required strength. Concrete tests shall be made in accordance with 
the Standard Methods of Making and Storing Specimens of Concrete 
in the Field (Appendix 14) and the Tentative Methods of Making 
Compression Tests of Concrete (Appendix 13). 

28.2 The proportions shall be 1 part of Portland cement, — " Proportions, 
parts of fine aggregate, and — '^ parts of coarse aggregate. The pro- 

* The engineer should strike out one of these terms. 

2 The engineer should indicate his choice of the method of proportioning to be used by striking 
out two of the Sections numbered 28. 

' The use of this method should be accompanied by a clause in the contract which indicates the 
procedure to be followed in case tests show that concrete of the specified strength has not been obtained. 

° The engineer should fill in these blanks. 



20 



Progress Report of Joint Committee 



portions of materials shall be selected from Table IV. In case the 
grading of the supply of available aggregate varies from that upon 
which the proportions were based, such aggregate may be used, 
provided the new proportions, as determined by the engineer, are 
such as to produce concrete of the required strength and quahty. 

B. Consistency. 

Consistency. 29. The engineer shall determine and specify the consistency of 

the concrete for various portions of the work based on tests of the 
materials to be used. The consistency of the concrete shall be 
measured by the slump test in the manner described in the Tentative 

Table II. — Workability of Concrete. 



Type of Concrete. 



1. Mass concrete 

2. Reinforced concrete: 

(a) Thin vertical sections and columns 

(6) Heavy sections 

(c) Thin confined horizontal sections . . 

3. Roads and pavements: 

(a) Hand finished 

(6) Machine finished 

4. Mortar for floor finish 



Maximum 

Slump, 

in. 



Specifications for Workability of Concrete for Concrete Pavements 
(Serial Designation : D 62-20 T) of the American Society for Testing 
Materials. (Appendix 12.) The slump for different types of con- 
crete shall not be greater than indicated in Table II. 

The consistency shall be checked from time to time during the 
progress of the work. 

a The engineer should insert the slumps required, based on tests called for in this section. The slump test require- 
ment is intended to insure concrete mixed with the minimum quantity of water required to produce a plastic mixture 
The following table indicates the maximum slump desirable for the various types of concrete, based on average 
aggregates and proportions: 



Type of Concrete. 


Maximum 

Slump, 

in. 


\. Mass concrete 


.-, 


2. Reinforced concrete: 

(a) Thin vertical sections and columns 


6 
2 


(c) Thin confined horizontal sections ■, . . . 

3. Roads and pavements: 

(a) Hand finished 


8 
4 




1 




2 







On Concrete and Reinforced Concrete. 21 

C. Mixing. 

30. Mixing, unless otherwise authorized by the engineer, shall be Machine 
done in a batch mixer of approved type, which will insure a uniform Mixing, 
distribution of the materials throughout the mass, so that the mixture 

is uniform in color and homogeneous. The mixer shall be equipped 
with suitable charging hopper, water storage, and a water-measuring 
device controlled from a case which can be kept locked and so con- 
structed that the water can be discharged only while the mixer is 
being charged. It shall also be equipped with an attachment for 
automatically locking the discharge lever until the batch has been 
mixed the required time after all materials are in the mixer. The 
entire contents of the drum shall be discharged before recharging. 
The mixer shall be cleaned at frequent intervals while in use. 

31. The mixing of each batch shall continue not less than 1 J- Time of 
minutes after all the materials are in the mixer, during which time ^^'°^" 
the mixer shall rotate at a peripheral speed of about 200 ft. per 
minute. The volume of the mixed material per batch shall not 
exceed the manufacturer's rated capacity of the mixer. 

32. When hand mixing is authorized by the engineer it shall be Hand 
done on a w^ater-tight platform. The materials shall be turned at ^^^^' 
least six times after the water is added and until the batch is homo- 
geneous in appearance and color. 

33. The re tempering of concrete or mortar which has partially Retempering. 
hardened, that is, remixing with or without additional cement, aggre- 
gate or water, shall not be permitted. 

VI. DEPOSITING CONCRETE. 

A. Depositifig in Air. 

34. Before beginning a run of concrete, hardened concrete and General, 
foreign materials shall be removed from the inner surfaces of mixing 

and conveying equipment. 

35. Before depositing concrete, debris shall be removed from the Approval, 
space to be occupied by the concrete; forms shall be thoroughly 
wetted (except in freezing weather) or oiled. Reinforcement shall be 
thoroughly secured in position and approved by the engineer. 

36. Concrete shall be handled from the mixer to the place of Handling, 
final deposit as rapidly as practicable by methods which shall prevent 

the separation or loss of the ingredients. It shall be deposited in the 
forms as nearly as practicable in its final position to avoid rehandling. 



22 



Progress Report of Joint Committee 



It shall be deposited in approximately uniform horizontal layers; the 
piHng up of the concrete in the forms in such manner as to permit the 
escape of the mortar from the coarse aggregate will not be permitted. 
Forms for walls or other thin section of considerable height, shall be 
provided with openings, or other devices that will permit the con- 
crete to be placed in a manner that will avoid accumulations of hard- 
ened concrete on forms or metal reinforcement. Under no circum- 
stances shall concrete that has partially hardened be deposited in 
the work. 

37. When concrete is conveyed by spouting, the plant shall be of 
such size and design as to insure a practically continuous flow in the 
spout. The angle of the spout with the horizontal shall be such as 
to allow the concrete to flow without separation of the ingredients.' 
The spout shall be thoroughly flushed with water before and after 
each run. The delivery from the spout shall be as close as possible 
to the point of deposit. When operation must be intermittent, the 
spout shall discharge into a hopper. 

38.. Concrete, during and immediately after depositing, shall be 
thoroughly compacted by means of rods or forks. For thin walls or 
inaccessible portions of the forms where rodding or forking is im- 
practicable, the concrete shall be assisted into place by tapping or 
hammering the forms. The concrete shall be thoroughly worked 
around the reinforcement, and around embedded fixtures, into the 
corners of the forms. 

39. Water shall be removed from excavations before concrete is 
deposited unless otherwise directed by the engineer. A continuous 
flow of water into the excavation shall be diverted through proper 
side drains to a sump, or by other approved methods which will avoid 
washing the freshly deposited concrete. 

40. Exposed surfaces of concrete subjected to premature drying 
shall be kept thoroughly wetted for a period of at least 7 days. 

41. Concrete mixed and deposited during freezing weather shall 
have a temperature of not less than 50° F. nor more than 100° F. 
Suitable means shall be provided for maintaining a temperature of 
at least 50° F. for not less than 72 hours after placing, or until the 
concrete has thoroughly hardened. The methods of heating the 
materials and protecting the concrete shall be approved by the 
engineer. Salt, chemicals or other foreign materials shall not be used 
to prevent freezing. 

* An angle of about 27 deg., or one vertical to two horizontal, is good practice. Spouting through 
a vertical pipe is satisfactory when the flow is continuous; when it is unchecked and discontinuous It 
is highly objectionable unless the flow is broken by baffles. 



On Concrete and Reinforced Concrete. 23 

42. Concrete shall be deposited continuously and as rapidly as Depositing 
practicable and until the unit of operation, as approved by the engineer, ^°°t»""ousiy. 
is completed. Construction joints at points not provided for in the 

plans shall be made in accordance with the provisions in-Section 69. 

43. The surface of the hardened concrete shall be roughened and Bonding, 
thoroughly cleaned of foreign matter and laitance, and saturated with 
water and forms retightened before depositing concrete. An excess 

of mortar on vertical or inclined surfaces shall be secured by 
thoroughly rodding or forking the freshly deposited concrete to remove 
the coarse aggregate from contact with the hardened'concrete. 

B. Rubble and Cyclopean Concrete. 

44. Rubble aggregate shall be thoroughly embedded in the Rubble 
concrete. The individual stones shall not be closer to any surface or Co^^^ete. 
adjacent stone than the maximum size of the coarse aggregate plus 

1 in. Each successive layer of concrete shall be keyed in accordance 
with the provision in Section 69. 

45. Cyclopean aggregate shall be thoroughly embedded in the Cyclopean 
concrete; no stone shall be closer to a finished surface than 1 ft., nor Concrete, 
closer than 6 in. to any adjacent stone. Stratified stone shall be laid 

on its natural bed. 

C. Depositing Under Water. ^ 

46. The methods, equipment, and materials to be used shall be General, 
submitted to and approved by the engineer before the work is started. 
Concrete shall be deposited by a method that will prevent the washing 

of the cement from the mixture, minimize the formation of laitance 
and avoid flow of water until the concrete has fully hardened. Con- 
crete shall be placed so as to minimize segregation of materials. Hand 
mixing will not be permitted. Concrete shall not be placed in water 
at temperatures below 35° F. 

47. Concrete deposited under water shall consist of not less than Proportions. 
1 part of Portland cement to 6 parts of fine and coarse aggregate, 
measured separately. 

48. Cofferdams shall be sufficiently tight to prevent flow of Cofferdams, 
water through the space in which concrete is to be deposited. Pump- 
ing will not be permitted while concrete is being deposited, nor until 

it has fully hardened. 

' Concrete should not be 'leposited under water if practicable to deposit in air. There is always 
uncertainty as to the results obtained from placing concrete under water; where conditions permit, 
the additional expense and delay of avoiding this method will be warranted. It is especially important 
that the aggregate be free from loam and other material which may cause laitance. Washed aggregates 
are preferable. Coarse aggregate consisting of washed gravel of a somewhat smaller size than used in 
open-air concrete work will give best results. Concrete should never be deposited under water without 
experienced supervision. Many failures, especially of structures in sea water, can be traced directly 
to Ignorance of proper methods or lack of expert supervision. 



24 



Progress Report of Joint Committee 



Depositing 49. Concrete shall be deposited continuously, keeping the top 

Continuously, surface as nearly level as possible, until it is brought above water, 
or to the required height. The work shall be carried on with suffi- 
cient rapidity to insure bonding of the successive layers. 

Method. 50. The following method^ shall be used for depositing concrete 

under water: 

(a) Tremie. — The tremie shall be water-tight and sufficiently 
large to permit a free flow of concrete. It shall be kept tilled^ at all 
times during depositing. The concrete shall be discharged and 
spread by raising the tremie in such manner as to maintain as nearly 
as practicable a uniform flow and avoid dropping the concrete through 
water. If the charge is lost during depositing the tremie shall be 
withdrawn and refilled. 

ib) Drop-Bottom Bucket.-— The bucket shall be of a type that 
cannot be dumped until it rests on the surface upon which the con- 
crete is to be deposited. The bottom doors when tripped shall open 
freely downward and outward. The top of the bucket shall be open. 
The bucket shall be completely filled, and slowly lowered to avoid 
back-wash. When discharged, the bucket shall be withdrawn slowly 
until clear of the concrete. 

(c) Bags. — Bags of jute or other coarse cloth shall be filled about 
two-thirds full of concrete and carefully placed by hand in a header- 
and-stretcher system so that the whole mass is interlocked. 

Laitance. 51. The concrete shall be disturbed as little as possible while it 

is being deposited, in order to avoid the formation of laitance. 
Laitance shall be removed. 



VII. FORMS. 



52. Forms shall conform to the shape, lines and dimensions of 
the concrete as called for on the plans. Lum_ber used in forms for 
exposed surfaces shall be dressed to a uniform thickness, and shall be 
free from loose knots or other defects. Joints in forms shall be hori- 
zontal or vertical. For unexposed surfaces and rough work, undressed 
lumber may be used. Lumber once used in forms shall have nails 
withdrawn, and surfaces to be in contact with concrete thoroughly 
cleaned, before being used again. 

53. Forms shall be substantial and sufficiently tight to prevent 



^ The engineer should strike out the method or methods inappUcable to the work. 

2 The tremie may be filled by one of the following methods: (I) Place the lower end in a box 
partly filled with concrete, so as to seal the bottom, then lower into position; (2) plug the tremie with 
cloth sacks or other material, which will be forced down as the tube is filled with concreteup fgl(; ) 
the end of the tremie with cloth sacks filled with concrete. 



On Concrete and Reinforced Concrete. 25 

leakage of mortar; they shall be properly braced or tied together so 
as to maintain position and shape. If adequate foundation for 
shores cannot be secured, trussed supports shall be provided. 

54. Bolts and rods shall preferably be used for internal ties; Workman- 
they shall be so arranged that when the forms are removed no metal ^^^^' 
shall be within 1 in. of any surface. Wire ties will be permitted only 

on Hght and unimportant work; they shall not be used through 
surfaces where discoloration would be objectionable. Shores sup- 
porting successive stories shall be placed diretly over those below, or 
so designed that the lead will be transmitted directly to them. Forms 
shall be set to line and grade and so constructed and fastened as to 
produce true lines. Special care shall be used to prevent bulging. 

55. Unless otherwise specified, suitable moldings or bevels shall Moldings. 
be placed in the angles of forms to round or bevel the edges of the 
concrete. 

56. The inside of forms shall be coated with non-staining mineral ouing. 
oil, or other approved material, or thoroughly wetted (except in 
freezing weather). Where oil is used, it shall be applied before the 
reinforcement is placed. 

57. Temporary openings shall be provided at the base of column inspection 
and wall forms, and other places where necessary to facilitate cleaning °^ Forms. 
and inspection immediately before depositing concrete. 

58. Forms shall not be disturbed until the concrete has ade- Removal of 
quately hardened, nor shall the permanent shores be removed until ^°^°^^' 
the structure has attained its full design strength' and all excess 
construction load has been removed. Wall and column forms shall 

be left in place until the concrete has hardened sufficiently to sustain 
its own weight and the construction loads likely to come upon it. 
Forms other than wall or column forms shall be left in place until the 
concrete has hardened sufhciently to carry the full load which it must 
sustain, unless removed in sections and each section of the structure 
is immediately re-shored. 

VIII. DETAILS OF CONSTRUCTION. 
A. Metal ReinJ or cement. 

59. Metal reinforcement, before being positioned, shall be Cleaning, 
thoroughly cleaned of mill and rust scale, and of coatings of any 
character that will destroy or reduce the bond. Reinforcement 
appreciably reduced in section shall be rejected. Reinforcement shall 

1 Many conditions affect the hardening of concrete and the proper time for the removal of the 
forms should be determined by a competent and responsible person. 



26 



Progress Report of Joint Committee 



Bending. 



Straightening. 



Placing. 



Splicing. 



Offsets in 
Column Rein- 
forcement. 



Future 
Bonding^ 



Moisture 
Protection. 



Fire 
Protection. 



be re-inspected and when necessary cleaned, where there is delay in 
depositing concrete. 

60. Reinforcement shall be carefully formed to the dimensions 
indicated on the plans or called for in the specifications. The radius 
of bends shall be 4 or more times the least diameter of the reinforce- 
ment bar. 

61. Metal reinforcement shall not be bent or straightened in a 
manner that will injure the material. Bars with kinks or sharp 
bends shall not be used. 

62. Metal reinforcement shall be accurately positioned, and 
secured against displacement by using annealed iron wire of not less 
than No. 18 gage or suitable clips at intersections, and shall be sup- 
ported by concrete or metal chairs, or spacers, or by metal hangers. 
Parallel bars shall not be placed closer in the clear than l| times the 
diameter of round bars or l| times the diagonal of square bars; if 
the ends of bars are hooked as specified in Section 130 the clear 
spacing may be made equal to the diameter of round bars or to 
the diagonal of square bars, but in no case shall the spacing between 
bars be less than 1 in., nor less than ij times the maximum size of the 
coarse aggregate. 

63. Splices of tension reinforcement at points of maximum stress 
shall be avoided. Splices, where required, shall provide sufficient lap 
to transfer the stress between bars by bond and shear, or by a mechan- 
ical connection such as a screw coupling. 

64. Vertical reinforcement shall be offset in a region where lateral 
support is afforded when changes in column cross-section occur and 
the vertical reinforcement bars are not sloped for the full length of the 
column. 

65. Exposed reinforcement bars intended for bonding with future 
extensions shall be protected from corrosion. 

B. Concrete Covering over Metal. 

66. Metal reinforcement in wall footings and column footings 
shall have a minimum covering of 3 in. of concrete. 

67. Metal reinforcement in fire-resistive construction shall be 
protected by not less than 1 in. of concrete in slabs and walls, and not 
less than 2 in. in beams, girders and columns, provided aggregate 
showing an expansion not materially greater than that of limestone or 
trap rock is used; when impracticable to obtain aggregate of this 
grade, the protective covering shall be 1 in. thicker and shall be rein- 
forced with metal mesh not exceeding 3 in. in greatest dimensions, 
placed 1 in. from the finished surface. 



On Concrete and Reinforced Concrete. 27 

The metal reinforcement in structures containing incombustible 
materials and in bridges where the lire hazard is limited, shall be 
protected by not less than f in. of concrete in slabs and walls and 
of not less than 1 J in. in beams, girders and columns. 

68. Plaster finish on an exposed concrete surface may be allowed piaster, 
to reduce the thickness of concrete protection required in Section 67 

by one-half the thickness of the plaster, but the protection shall not 
be less than that specified in Sections 66 and 67, 

C. Joints. 

69. Construction joints not indicated on the plans nor specified Construction 
shall be located and formed so as to least impair the strength and J°^"*s. 
appearance of the structure'. Horizontal construction joints shall be 

formed by embedding stones projecting above the surface or by 
roughening the surface in contact, or by mortises or keys formed in 
the concrete. Sufiicient section shall be provided in horizontal as 
well as vertical keys to resist shear. 

70. Construction joints in columns shall be made at the under- joints in 
side of the floor. Haunches and column capitals shall be considered Columns, 
as part of and built monolithic with the floor construction. 

7 1 . Construction joints in floors shall be located near the center joints in 
of spans of slabs, beams, and girders, unless a beam intersects a floors, 
girder at this point, in which case the joints in the girders shall be 
oft'set a distance equal to twice the wadth of the beam. Adequate 
orovision shall be made for shear either by sufficient reinforcement, or 

by sloping the joint so as to provide an inclined bearing. 

72. Girders and beams designed to be monolithic with walls Monouttic 
and columns, shall not be cast until 2 hours after the completion of Construction, 
the walls or columns. 

73. Construction joints made crosswise of a building 100 ft. or Construction 
more in length, shall have special reinforcement placed at right angles Jo^^*^ m 

to the joint and extending a sufiicient distance on each side of the Buildings, 
joint to develop the strength of the reinforcement by bond. This 
reinforcement shall be placed near the opposite face of the member 
from the main tension reinforcement; the amount of such reinforce- 
ment shall be not less than 0.5 per cent of the section of the members 
cut by the joint. 

74. Expansion joints shall be so detailed that the necessary Expansion 
movement may occur with the minimum of resistance at the joint. J^^^^s. 
The structure adjacent to the joint shaU preferably be supported on 
separate columns or walls. Reinforcement shall not extend across 

an expansion joint. The break between the two sections shall be 



28 



Progress Report of Joint Committee 



complete, and may be effected by a coating of white lead and oil, 
asphalt paint or petrolatum, or by building paper, placed over the 
entire surface of the hardened concrete. Exposed edges of expan- 
sion joints in walls or abutments shall be bonded. Exposed expan- 
sion joints formed between two distinct concrete members shall be 
filled with an elastic joint filler of approved quahty. 

75. Structures exceeding 200 ft. in length and of width less than 
about one-half the length, shall be divided by means of expansion 
joints, located near the middle, but not more than 200 ft. apart, to 
minimize the destructive effects of temperature changes and shrinkage. 
Structures in which marked changes in plan section take place 
abruptly,, or within a small distance, shall be provided with expansion 
joints at the points where such changes ill section occur. 

76. The seat of sliding joints shall be finished with a smooth 
troweled surface and shall not have the superimposed concrete placed 
upon it until it has thoroughly hardened. In order to facilitate 
sliding, two thicknesses of building paper shall be placed over the 
seat on which the superimposed concrete is to be deposited. 

77. When it is not possible to finish a section of the structure in 
one continuous operation and water-tight construction is required, the 
joints shall be prepared as follows: The surface of the first section of 
concrete shall be provided with continuous key- ways. All laitance 
and other foreign substances shall be removed from the surface of 
the concrete first placed; this surface shall then be thoroughly satu- 
rated with water and given a heavy coating of neat cement. The 
next section of concrete shall be placed in such manner as to insure 
an excess of mortar over the entire surface of the joint. Where 
shown on the plans, the joint shall be so constructed as to permit of 
its being caulked with oakum. 



IX. WATERPROOFING AND PROTECTIVE TREATMENT. 
A. Waterproofing. 

78. The requirements for quality of concrete in Section 28 shall 
be strictly followed. Particular attention shall be given to work- 
manship. 

79. Integral compounds shall not be used. 

80. Membrane waterproofing shall be used in basements, pits, 
shafts, tunnels, bridge floors, retaining walls and similar structures, 
where an added protection is desired. 

81. See Section 77. 



On Concrete and Reinforced Concrete. 29 

B. Oilproojing. 

82. Concrete structures for containing light mineral oils, animal ouproofing. 
oils, certain vegetable oils and other commercial liquids shall be 

given a special coating which shall be applied immediately after con- 
struction. Floors or other surfaces exposed to heavy concentrations 
of such oils or liquids shall be similarly protected. The treatment to 
be applied shall be approved by the engineer. 

C. Concrete in Sea Water. 

83. Plain concrete in sea water or exposed directly along the sea Proportions, 
coast shall contain not less than ij bbl. (6 bags) of Portland cement 

per cubic yard in place; concrete from 2 ft. below low water to 2 ft. 
above high water, or from a plane below to a plane above wave action, 
shall be made of a mixture containing not less than if bbl. (7 bags) 
of Portland cement per cubic yard in place. Slag, broken brick, soft 
limestone, soft sandstone or other porous or weak aggregates shall not 
be used. 

84. Concrete shall not be deposited under sea water unless Depositing, 
unavoidable, in which case it shall be placed in accordance with the 
methods described in Sections 48 to 51. Sea water shall not be 
allowed to come in contact with the concrete until it has hardened 

for at least 4 days. Concrete shall be placed in such a manner as 
to avoid horizontal or inclined seams or work planes. The placing of 
concrete between tides shall be a continuous operation, in accordance 
with the methods described in Section 42; where it is impossible to 
avoid seams or joints proceed as in Section 43. 

85. Metal reinforcement shall be placed at least 3 in. from any Protection, 
plane or curved surface, and at corners at least 4 in. from all adjacent 
surfaces. Metal chairs, supports, or ties shall not extend to the 
surface of the concrete. Where unusually severe conditions of 
abrasion are anticipated, the face of the concrete from 2 ft. below low 

water to 2 ft. above high water, or from a plane below to a plane 
above wave action, shall be protected by creosoted timber, dense 
vitrified shale brick, or stone of suitable quality, as designated on the 
plans. 

86. The consistency shall be such as to produce concrete which Consistency, 
for mass work shall give a slump of not more than 2 in., and for 
reinforced concrete a slump of not more than 4 in. 

D. Concrete in Alkali Soils or Water. 

87. Concrete below the ground-line shall contain not less than Proportions. 
if bbl. (7 bags) of Portland cement per cubic yard in place. 



30 



Progress Report or Joint Committee 



Consistency. 

Placing. 

Curing. 
Protection. 

General. 



Top Surfaces 
not Subject 
to Wear. 



88. The consistency of the concrete shall be such as to produce 
a slump of not more than 2 in., and for small members in which 
aggregates coarser than f in. cannot be used, a slump of not more 
than 6 in. 

89. Concrete should be placed in such a manner as to avoid 
horizontal or inclined seams, or work planes; where this is impossible 
the requirements of Section 69 shall be followed. 

90. Concrete shall be kept wet with fresh water for not less than 
7 days following placing. 

91. Metal reinforcement or other corrodible metal shall not be 
placed closer than 2 in. to the faces of members exposed to alkali 
soil or water. 

X. SURFACE FINISH. 

92. Concrete to have exposed surfaces with specified finish shall 
be mixed, placed and worked to secure a uniform distribution of the 
aggregates, and insure uniform texture of surface.^ Placing shall be 
continuous throughout each distinct division of an area. Joint lines 
shall be located at indicated points. Voids which appear upon 
removal of the forms shall be drenched with water and be immediately 
filled with material of the same composition as that used in the 
surface, and smoothed with a wood spatula or float. Fins or offsets 
shall be neatly removed. The work shall be finished free from 
streaks. 

93. Top surfaces not subject to wear shall be smoothed with a 
wood float and be kept wet for at least 7 days. Care shall be taken 
to avoid an excess of water in the concrete, and to drain off or other- 
wise promptly remove any water that comes to the surface. Dry 
cement, or a dry mixture of cement and sand, shall not be sprinkled 
directly on the surface. 



One-Course 
Work. 



A. Wearing Surfaces. 

94. Aggregates for the wearing surface shall have a high resistance 
to abrasion. -They shall be carefully screened and thoroughly washed. 
The least quantity of mixing water that will produce a dense concrete 
shall be used. The mix shall not be leaner than 1 part of Portland 
cement and 2j parts of aggregate. The surface shall be screeded 
even and finished with a wood float. Excess water shall be promptly 
drained off or otherwise removed. Overtroweling shall be avoided. 



1 This is accomplished by uniform proportioning of ingredients, and thorough mixing with the 
proper amount of water; after placing, the concrete should be thoroughly rodded or forked to force 
the aggregate against the face forms and prevent the formation of voids. 



On Concrete and Reinforced Concrete. 31 

95. In two-course work the wearing surface shall be placed Two-Course 
within J hour after the base course. °^ * 

If the wearing surface is required to be applied to a hardened 
base course, the latter shall be prepared by roughening with a pick or 
other effective tool, thoroughly drenching with water until saturated 
and covered with a thin layer of neat cement immediately before the 
wearing surface is placed. 

The finished wearing course in two-course work shall not be 
thinner than 1 in. 

96. Concrete wearing surfaces constructed in accordance with Curing. 
Sections 94 and 95, shall be kept wet' for at least 10 days in the case 

of floors and 21 days in the case of roads and pavements. 

97.2 Terrazzo finish shall be constructed by mixing 1 part of Terrazzo 
Portland cement, 2^ parts of crushed marble which will pass through ^"^^ * 
a I -in. screen and is free from dust, and sufficient water to produce 
a dense concrete, which shall be spread on the base course and worked 
down to a thickness of 1 in. by patting or rolling and troweling. 

The surface shall be kept wet for not less than 10 days and after 
thoroughly curing shall be rubbed to a plane surface with a stone or a 
surfacing machine. Hardened concrete to which a terrazzo finish is 
to be applied shall be prepared as prescribed in Section 95. 

97.2 Terrazzo finish shall be constructed by mixing 1 part of Terrazzo 
Portland cement, 2 parts of sand and sufficient water to produce a ^^^^^• 
plastic mortar, which shall be spread on the base course to a depth 
of 1 in. Crushed marble, which will pass through a |-in. screen and 
is free from dust, shall be sprinkled over the surface of the fresh 
mortar and pressed or rolled in. 

The surface shall be kept wet for not less than 10 days and after 
thoroughly curing shall be rubbed to a plane surface with a stone or a 
surfacing machine. Hardened concrete to which a terrazzo finish is 
to be applied shall be prepared as prescribed in Section 95. 

B. Decorative Finishes. 

98. Concrete shall be wetted immediately after the formes are Rubbed 
removed and rubbed even and smooth with a carborundum brick, or ^'"•^^• 
other abrasive, and to uniform appearance without applying any 
cement or other coating. 



1 Prevention of premature drying during the early hardening of concrete is essential to the develop- 
ment of high resistance to abrasion. The surface may be covered with a layer of burlap, earth or 
sand, kept wet, or it may be divided into small areas by dikes and flooded with water to a depth of 
2 or 3 in. 

- The engineer should strike out one of the two Sections numbered 97. 



32 



Progress Report of Joint Committee 



Scrubbed 
Finish. 



Sand Blast 
Finish. . 



Tooled 
Finish. 



Sand Floated 
Finish. 



Colored 

Aggregate 

Finish. 



Colored 
Pigment 
Finish. 



99. The face forms shall be removed as soon as the concrete has 
hardened sufficiently. Voids shall be immediately filled with mortar 
of the same composition as that used in the face. Fins and other 
unevennesses shall be rubbed off and the whole surface be scrubbed 
with fiber or wire brushes, using water freely, as the degree of hard- 
ness may require, until the aggregate is uniformly exposed; the sur- 
face shall then be rinsed with clean water. The corners shall be 
sharp and unbroken. If portions of the surface have become too 
hard to scrub in uniform relief, dilute hydrochloric acid (l part of 
acid to 4 parts of water) may be used to facilitate scrubbing of 
hardened surfaces. The acid shall be thoroughly washed off with 
clean water. 

100. Immediately following removal of forms, voids shall be 
filled with mortar of the same composition as that used in the face 
and allowed to harden. Unevennesses and form marks shall be 
removed by chipping or rubbing; the face shall then be cut with an 
air blast of hard sand with angular grains until the aggregate is in 
uniform relief. 

101. The surface shall be permitted to become hard and dry 
before tooling. The cutting shall remove the entire skin and produce 
a uniform surface true to lines. 

102. The forms shall be removed before the surface has fully 
hardened; the surface shall be rubbed with a wooden float by a 
uniform circular motion, using fine sand until the resulting finish is 
even and uniform. 

103. Colored or other special aggregate used for finish shall be 
exposed by scrubbing as provided in Section 99. Facing mortar of 
1 part of Portland cement, ij parts of sand, and 3 parts of screen- 
ings or pebbles shall be placed against the face forms to a thickness 
of about 1 in. sufficiently in advance of the body concrete to prevent 
the latter coming in contact with the form. 

104. Mineral pigment shall be thoroughly mixed dry with the 
Portland cement and fine aggregate; care shall be taken to secure a 
uniform tint throughout. 

XI. DESIGN. 



General 
Assumptions. 



A. General Assumptions. 

105. The design of reinforced concrete members under these 
specifications shall be based on the following assumptions: 

(a) Calculations are made with reference to working stresses and 
safe loads rather than with reference to ultimate strength and ultimate 
loads. 



On Concrete and Reinforced Concrete. 33 

(b) A plane section before bending remains plane after bending. 

(c) The modulus of elasticity of concrete in compression is con- 
stant within the limits of working stresses; the distribution of com- 
pressive stress in beams is therefore rectilinear. 

(d) The values for the modulus of elasticity of concrete in com- 
putations for the position of the neutral axis, for the resisting moment 
of beams and for compression of concrete in columns, are as 
follows : 

(1) 1/40 that of steel, when the compressive strength of the 

concrete at 28 days is below 800 lb. per sq. in.; 

(2) 1/15 that of steel, when the compressive strength of the 

concrete at 28 days hes between 800 and 2200 lb. per 
sq. in.; 

(3) l/l2 that of steel, when the compressive strength of the 

concrete at 28 days lies between 2200 and 2900 lb. 
per sq. in.; 

(4) 1/10 that of steel, when the compressive strength of 

the concrete at 28 days is higher than 2900 lb. per 
sq. in.; 

(5) 1/8 that of steel for calculating the deflection of rein- 

forced concrete beams which are free to move longi- 
tudinally at the supports, and in which the tensile 
resistance of the concrete is neglected. 

(e) In calculating the moment of resistance of reinforced concrete 
beams and slabs the tensile resistance of the concrete is neglected. 

(/) The adhesion between the concrete and the metal reinforce- 
ment remains unbroken throughout the range of working stresses. 
Under compression the two materials are therefore stressed in pro- 
portion to their moduH of elasticity. 

(g) Initial stress in the reinforcement due to contraction or 
expansion of the concrete is neglected, except in the design of rein- 
forced concrete columns. 

B. Flexure of Rectangular Reinforced Concrete Beams and Slabs. 

106. Computations of flexure in rectangular reinforced concrete Flexure 
beams and slabs shall be based on the following formulas : Formulas. 

(a) Reinforced for Tension Only. 
Position of neutral axis. 



k = V2pn-^(pny-pn (0 



34 Progress Report or Joint Committee 

Arm^ of resisting couple, 

■'-'-; « 

Compressive unit stress^ in extreme fiber of concrete, 

''-m'f '=' 

Tensile unit stress^ in longitudinal reinforcement, 

f,^^^^_ (4) 

■^ AJd pjbd' 

Steel ratio for balanced reinforcement, 

'''wi^ '" 

For formulas on shear and bond, see Sections 120 and 140. 

(b) Reinforced for Both Tension and Compression. 
Position cf neutral axis, 

k = \2nip+p'^\ +n'(p+py - n(p+p') (6) 

Position of resultant compression, 

\kH+2p'nd'ik- — 

'- / d'^' W 

k'^^-lp'nik — 

Arm^ of resisting couple, 

jd = d — z (8) 

Compressive unit stress^ in extreme fiber of concrete, 

.'"-[--^('-f)(-f)] *" 

Tensile unit stress' in longitudinal reinforcement, 

f^ = JL = nf)-± (10) 

1 For /jj=16,000 to 18,000 lb. per sq. in. and /^^SOO to 900 lb. per sq. in., j may be assumed as 
0.86. For values of pn varying from 0.04 to 0.24, jk is approximately equal to 0.67 yj >.„ 



On Concrete and Reinforced Concrete. 35 

Compressive unit stress' in longitudinal reinforcement, 

/',. = <^^ (11) 

107. The symbols^ used in Formulas 1 to 23 are defined as follows: Notation. 

As = effective cross-sectional area of metal reinforcement in ten- 
sion in beams; 

b = width of rectangular beam or width of flange of T-beam; 

d = depth from compression surface of beam or slab to center 
of longitudinal tension reinforcement; 

d^ = depth from compression surface of beam or slab to center 
of compression reinforcement; 

fc = compressive unit stress in extreme fiber of concrete ; 

fs = tensile unit stress in longitudinal reinforcement; 

fs = compressive unit stress in longitudinal reinforcement; 

// = unsupported length of column; 

/ = moment of inertia of a section about the neutral axis for 
bending; 

j = ratio of lever arm of resisting couple to depth d; 

k = ratio of depth of neutral axis to depth d; 

J = span length of beam or slab (generally distance from cen- 
ter to center of supports — see Section 108) ; 

M = bending moment or moment of resistance in general; 

n = Es/Ec = ratio of modulus of elasticity of steel to that of 
concrete; 

p = ratio of effective area of tension reinforcement to effective 
area of concrete in beams = Ag/bd; 

p' = ratio of effective area of compression reinforcement to 
effective area of concrete in beams; 

w = uniformly distributed load per unit of length of beam or 
slab ; 

z = depth from compression surface of beam or slab of result- 
ant of compressive stresses. 

108. The span length, I, of freely supported beams and slabs, Span Length, 
shall be the distance between centers of the supports, but shall not 

exceed the clear span plus the depth of beam or slab. The span length 
for continuous or restrained beams built monolithically with supports 
shall be the clear distance between faces of supports. Where brackets 
having a width not less than the width of the beam and making an 



See footnote, p. 34, 

For illustration of notation as applied to typical beams or slabs, see Figs. 1 and 2. 



36 



Progress Report of Joint Committee 



Moments in 
Freely 
Supported 
Beams of 
Equal Span. 



angle of 45 deg. or more with the axis of a restrained beam are built 
monolithic with the beam and support, the span shall be measured 
from the section where the combined depth of the beam and bracket 
is at least one-third more than the depth of the beam. Maximum 
negative moments are to be considered as existing at the ends of the 
span, as above defined. No portion of a bracket shall be considered 
as adding to the effective depth of the beam. 

109. The following moments at critical sections of freely supported 
beams and slabs of equal spans carrying uniformly distributed loads 
shall be used: 

(a) Maximum positive moment in beams and slabs of one span, 



M 



rf 



(12) 



{b) Center of slabs and beams continuous for two spans only, 
(l) Positive moment at the center, 



M = 



10 



(2) Maximum negative moment, 



M = 



(1.3) 



(14) 



(c) Slabs and beams continuous for more than two spans, 
(l) Center and supports of interior spans, 



M = 



12 



(2) Center and interior support of end spans, 



M = — 

10 



(15) 



(16) 



(d) Negative moment at the supports of slab or beam built into 
brick or masonry walls in a manner that develops partial 
end restraint, 



M = not less than 



16 



(17) 



110. The following moments at the critical sections of beams or 
5 of equal spans cast monolithic with columns or si] 
and carrying uniformly distributed loads shall be used : 



Moments in 

oiithTc^with"' sl^^s ^f equal spans cast monohthic with columns or similar supports 

Supports. 



On Concrete and Reinforced Concrete. 37 

(a) Supports of intermediate spans, 

M=^^ (18) 

12 

(b) Center of intermediate spans, 

ilf = ^ (19) 

16 

(c) Beams in which /// is less than twice the sum of ' the values 

of / h for the exterior columns above and below which are 
built into the beam, 

(1) Center and first interior support, 

M = '^ .- (20) 

12 

(2) Exterior supports, 

M = ^ (21) 

12 

(d) Beams in which /// is equal to, or greater than, twice the sum 

of the values of I/h for the exterior columns above and 
below which are built into the beam, 

(1) Center of span and at first interior support of end span, 

M = ?^ : (22) 

(2) Exterior support, 

M = ^^ (23) 

16 

111. Continuous beams with unequal spans, whether freely sup- Moment 
ported or cast monoHthic with columns, shall be analyzed to determine Coefficients of 
the actual moments under the given conditions of loading and restraint. Beams. 
Provision shall be made for negative moment occurring in short spans 
adjacent to longer spans when the latter only are loaded. 

C. Flexure of Reinforced Concrete T-Beams. 

112. Computations of flexure in reinforced concrete T-beams shall Flexure 
be based on the following formulas: Formulas. 

{a) Neutral Axis in the Flange. 

Use formulas for rectangular beams and slabs in Section 106. 



38 Progress Report of Joint Committee 

(b) Neutral Axis below the Flange} 
Position of neutral axis, 

,,^2ndA,+bt (24) 

2nAs+2bt 

Position of resultant compression, 

^^(3kd-2t\j^ 

\2kd-tl 3 
Arm of resisting couple, 

jd = d-z (26) 

Compressive unit stress in extreme fiber of concrete, 

f= ^kd ^L(A.] (27) 

•^" bt{kd-it)jd n\l-k/'"""" 

Tensile unit stress in longitudinal reinforcement, 

/, = ^ (28) 

Formulas 24, 25, 26, 27 and 28 neglect compression in the stem.^ 

113. The symbols^ used in Formulas 24 to 28 are defined in 
Section 107, except as follows: 

y = width of stem of .T-beam; 

/ = thickness of flange of T-beam; 

114. Effective and adequate bond and shear resistance shall be 
provided in beam-and-slab construction at the junction of the beam 
and slab; the slab shall be built and considered an integral part of 
the beam; the effective flange width shall not exceed one-fourth of 
the span length of the beam, and its overhanging width on either side 

1 For approximate results the formulas for rectangular beams, Section 106, may be used. 

2 The following formulas take into account the compression in the stem ; they are recommended 
where the flange is small compared with the stem : 

Position of neutral axis, 

\ P ^ b' ^ b' 

Position of resultant compression, 

. _ (kdt^-mb+[ikd-tni+Ukd-t))] b ' 

t{2kd-t)b+{kd-tyb' ^'^^'^^ 

Arm of resisting couple (see footnote Section 106), 

jd=d~z (26o) 

Compressive unit stress in extreme fiber of concrete, 

^'^~ [{2kd—t)bt+{kd—t)^b'] jd'" ^ ' 

Tensile unit stress in longitudinal reinforcement, 

^'=XJi ••««•> 

' For illustration of certain symbols as applied to typical T-beams, see Fig. 3, 



On Concrete and Reinforced Concrete. 39 

of the web shall not exceed 8 times the thickness of the slab nor one- 
half the clear distance to the next beam. 

115. The unsupported length of the compression flange of a Flange 
T-beam shall not exceed 36 times the least width of the beam. Length. 

116. Where the principal slab reinforcement is parallel to the Transverse 
beam, transverse reinforcement, not less in amount than 0.3 per cent R^inforce- 

^ ment. 

of the sectional area of the slab, shall be provided in the top of the 
slab and shall extend over the beam and into the slab not less than 
two-thirds of the effective flange overhang. The spacing of the bars 
shall not exceed 18 in. 

117. Provision shall be made for the compressive stress at the Compressive 
support in continuous T-beam construction. Supports. 

118. The flange of the slab shall not be considered as effective in shear, 
computing the shear and diagonal tension resistance of T-beams. 

119. Isolated beams in which the T-form is used only for the isolated 
purpose of providing additional compression area, shall have a flange ^^°^^' 
thickness not less than one-half the width of the web and a total 
flange width not more than 4 times the web thickness. 

D. Diagonal Tension and Shear. 
a. Formulas and Notation. 

120. Diagonal tension and shear in reinforced concrete beams Formulas, 
shall be calculated by the following formulas: 

Shearing unit stress,' 

. = i^ (29) 

bjd 

Stress' in vertical web reinforcement, 

f^ = -pi (30) 

A,jd 

121. The symbols used in Formulas 29 to 36 are defined in Notation. 
Section 107, except as follows: 

a = spacing of web reinforcement bars measured perpendicular 

to their direction; 
Ay = total area of web reinforcement in tension within a distance 

of a (oi, ao, as, etc.) or the total area of all bars bent up 

in any one plane; 
a = angle between web bars and longitudinal bars; 
/^ = tensile unit stress in web reinforcement; 
= perimeter of bar; 
%o = sum of perimeters of bars in one set; 

1 Approximate results may be secured by assuming j =0.875, 



40 



Progress Report or Joint Committee 



u 

V 

V 

r 



= ratio of cross-sectional area of negative reinforcement which 
crosses entirely over the column capital of a fiat slab or 
over the dropped panel, to the total cross-sectional area 
of the negative reinforcement in the two column strips; 

= spacing of web members, measured at the neutral axis 
and in the direction of the longitudinal axis of the beam: 

= bond stress per unit of area of surface of bar; 

= shearing unit stress; 

= total shear; 

= external shear on any section after deducting that carried 
by the concrete. 



Web or 
Bent-up Bars. 



b. Beams Without Web Reinforcement. 

122. The shearing unit stress in beams in which the longitudinal 
reinforcement is designed to meet all moment requirements, but with- 
out special anchorage, shall not exceed 0.02 f c, but in no case 
shall it exceed 40 lb. per sq. in. Adequate reinforcement shall be 
provided at all sections where negative moment occurs in beams con- 
tinuous over supports or built into walls or columns at their ends. 
(For typical design, see Fig. 4.) 

123. The shearing unit stress in beams in which longitudinal 
reinforcement is anchored by means of hooked ends or otherwise, as 
specified in Section 130, shall not exceed 0.03 f c- Adequate rein- 
forcement for both positive and negative moment shall be provided 
at all sections where maximum moment exists. (For typical design, 
see Fig. 5.) 

c. Beams With Web Reinforcement. 

124. When the shearing unit stress calculated by Formula 29 
exceeds the values specified in Sections 122 and 123, web reinforcement 
shall be provided by one or more of the following methods : 

{a) Series of vertical stirrups or web bars ; 

{b) Series of inclined stirrups or web bars ; 

(c) Series of bent-up longitudinal bars; 

{d) Longitudinal bars bent up in a single plane. 

Provision against bond failure of the web reinforcement shall be 
as specified in Section 131. (For typical designs, see Figs. 6 and 7. 
For typical detail of anchorage of longitudinal bars and vertical 
stirrups, see Fig. 8.) 

125. Where web reinforcement is present and where longitudinal 
reinforcement is provided to meet all moment requirements, the con- 
crete may be assumed to carry a shearing unit stress not greater than 



On Concrete and Reinforced Concrete. 41 

0.02 /c and not greater in any case than 40 lb. per sq. in. In the 
case where a series of web bars or bent-up longitudinal bars is used, 
the web reinforcement shall be designed according to the formula : 

A, = --= ^-^^^ (31) 

f.jd f,jd 

(For typical design, see Fig. 9.) 

126. Where the web reinforcement consists of bars bent up in a Bars Bent Up 
single plane at an angle so as to reinforce all sections of the beam in ^^ Single 
which th^ shearing unit stress on the web concrete exceeds 0.02/',., the 
concrete may be assumed to take a shearing unit stress not greater than 

0.02 f\, and not greater than 40 lb. per sq. in.; the remainder of the 

shear shall be carried by the bent-up bars designed according to 

the formula: 

V 

A. -y-~— (32) 

/j; sm a 

In case the web reinforcement consists solely of bent bars, the first 
bent bar shall bend downward from the plane of the upper reinforce- 
ment at the plane of the edge of the support or between that plane 
and the center of the support. (For typical design, see Fig. 10.) 

127. Where two or more types of web reinforcement are used in Combined 
conjunction, the total shearing resistance of the beam shall be taken T^^ ^^^^' 
as the sum of the shearing resistance as computed for the various 

types separately.^ 

128. Where there is no special mechanical anchorage of the longi- Maximum 
tudinal reinforcement, the shearing unit-stress shall not exceed 0.06 f c unif sT^ 
irrespective of the web reinforcement used. 

129. Where special mechanical anchorage of the longitudinal Special 
reinforcement as prescribed in Section 130 is provided, the shearing Mechamcai 
unit stress as computed by Formula 29 may be greater than 0.06 f'^. 

but in no case shall it exceed 0.\2f\.^ In this case the concrete may 
be assumed to take a shearing unit stress of not more than 0.025 f'^, 
but not more than 50 lb. per sq. in. 

130. Special mechanical anchorage of the longitudinal reinforce- Anchorage of 
ment for positive moment may consist of carrying the bars beyond the Rei^nfor^e-^^ 
point of inflection of restrained or continuous members a sufficient ment. 
distance to develop by bond between the point of inflection and the 

end of the bar a tensile stress equal to one-third the safe working 

1 In such computation the shearing value of the concrete in the web shall be included once only. 

' The limit 0.12/'^ is based on the ultimate bearing unit stress of 0.5/'^ at which beams reinforced 
with vertical stirrups fail due to diagonal compression in the webs. A higher value than 0. 1 2 //^ may 
be permitted in beams with inclined web reinforcement, but it is not thought necessary to allow such 
higher limit to meet the needs of design practice. 



42 Progress Report or Joint Committee 

stress in the reinforcement. If such a bar is straight, it shall extend 
to within 1 in. of the center of the support, or in the case of wide 
supports shall extend not less than 12 in. beyond the face of the 
support. Special mechanical anchorage may also be secured by bend- 
ing the end of the bar over the support in a full semi-circle to a diameter 
not less than 8 times the diameter of the bar, the total length of the 
bend being not less than 1 6 diameters of the bar. Any other mechanical 
device that secures the end of the bar over the support against slipping 
without stressing the concrete in excess of 0.5 f'^ in local coiyipression 
may be used, provided such device does not tend to spht the concrete. 
Negative reinforcement shall be thoroughly anchored at or across the 
support or shall extend into the span a sufficient distance to develop 
by bond the tensile, stresses due to negative moment. In the case of 
freely supported ends of continuous beams, special mechanical an- 
chorage shall be provided, which is capable of developing at the end 
of the span a tensile stress which is not less than one-third of the safe 
tensile stress of the bar at the point of maximum moment. (For 
illustrative design, see Fig. 1 1 .) 

Anchorage of 131. Anchorage of the web reinforcement shall be by one of the 

Web Rein- following methods : 

forcement. o 

{a) Continuity of the web bar with the longitudinal bar; 

ih) Carrying the web bar around at least two sides of a longi- 
tudinal bar at both ends of the web bar ; or 

{c) Carrying the web bar about at least two sides of a longitudinal 
bar at one end and making a semi-circular hook at the other end 
which has a diameter equal to that of the web bar. 

In all cases the bent ends of web bars shall 'extend at least 8 
diameters below or above the point of extreme height or depth of the 
web bar. In case the end anchorage of the web member is not in 
bearing on other reinforcement, the anchorage shall be such as to 
engage an adequate amount of concrete to prevent the bar from 
pulling off a portion of the concrete. In all cases the stirrups shall 
be carried as close to the upper and lower surfaces as iireprooiing 
requirements will permit. (For typical designs, see Figs. 8 and 12.) 
Size of 132. The size of web reinforcement bars which are neither a part 

Web Bars. ^f ^^iq longitudinal bars nor welded thereto, shall be such that not less 
than two-fifths of the allowable tensile stress in the bar may be 
developed by bond stresses in a length of bar equal to 0.4 J. ^ The 
remainder of the tensile stress in the bar shall be provided for by 
adequate end anchorage as specified in Section 131. 



^ This condition is satisfied for plain round stirrups when the diameter of the bar does not exceed 
d/50. 



Ox Concrete and Reinforced Concrete. 43 



133. Shearing unit stress shall be computed on the full width of Breadth 

Beams 
Shear. 



or 

rectangular beams, on the width of the stem of T-beams, and on the ^h^^ ^^ 
thickness of the web in beams of I-section. 

134. The shearing stress in tile-and-concrete-beam construction Shear in 
shall not exceed that in beams or slabs with similar reinforcement. Jeam-and- 

Tile 

The width of the effective section for shear as governing diagonal Construction, 
tension shall be taken as the thickness of the concrete web plus one- 
half the thickness of the vertical webs of the, tile. (For typical design, 
see Fig. 13.) 

135. The spacing, a, of web reinforcement bars shall be measured Spacing of 
perpendicular to their direction and in a plane parallel to the longi- J^^^ ^em- 
tudinal axis of the beam. The spacing shall not exceed | ^ in any 

case where web reinforcement is necessary. Where vertical stirrups 
are used, or where incHned web bars make an angle more than 60 deg. 
with the horizontal, the spacing shall not exceed ^ d. Where the 
shearing unit stress exceeds 0.06 f\, the spacing of the web reinforce- 
ment shall not exceed J d in any case, nor | d for vertical stirrups or 
web reinforcement making an angle more than 60 deg. with the hori- 
zontal. The first shear reinforcement member shall cross the neutral 
axis of the member at a distance from the face of the support, meas- 
ured along the axis of the beam, not greater than J d, nor greater than 
the spacmg of web members as determined for a section taken at the 
edge of the support. Web members may be placed at any angle 
between 20 and 90 deg. with the longitudinal bars, provided that 
if inclined they shall be incKned in such a manner as to resist the 
tensile stress in the web. 

d. Flat Slabs. 

136. The shearing unit stress shall not exceed the value of v in shearing 
the formula. ^^^""• 

v = 0.02f\{l+r) :...(33) 

nor in any case shall it exceed 0.03 f'c- 

The unit shearing stress shall be computed on 

(a) A vertical section which has a depth in inches of I (/i— li) 
and which hes at a distance in inches of /i — ij from the edge of the 
column capital; and 

(b) A vertical section which has a depth in inches of | (/-i— if) 
and which hes at a distance in inches of U—l^ from the edge of the 
dropped panel. 

In no case shall r be less than 0.25. Where the shearing stress 
on section (a) is being considered, r shall be taken as the proportional 
amount of reinforcement crossing the column capital; where the 



44 



Progress Report of Joint Committee 



Shear and 
Diagonal 
Tension in 
Footings. 



Critical 
Section fcr 
Soil Footings 



Critical 
Section for 
Pile Footings. 



shearing stress at section (b) is being considered, r shall be taken as 
the proportional amount of reinforcement crossing entirely over the 
dropped panel. (For typical fiat slab and designation of principal 
design sections, see Figs. 14 and 15.) 

e. Footings. 

137. The shearing stress shall be computed by Formula 29. When 
so computed the stress on the critical section defined below, or on 
sections outside of the critical section, shall not exceed 0.02 f\ for 
footings with straight reinforcement bars, nor 0.03 f\ for footings in 
which the reinforcement bars are anchored at both ends by adequate 
hooks or otherwise as specified in Section 130. 

138. The critical section for diagonal tension in footings bearing 
directly on the soil shall be taken on a vertical section through the 
perimeter of the lower base of a frustum of a cone or pyramid which 
has a base angle of 45 deg. and has for its top the base of the column 
or pedestal and for its lower base the plane of the center of longitu- 
dinal reinforcement. 

139. The critical section for diagonal tension in footings bearing 
on piles shall be taken on a vertical section at the inner edge of the 
first row of piles entirely outside a section midway between the face 
of the column or pedestal and the section described in Section 138 for 
soil footings, but in no case outside of the section described in Section 
138. The critical section for piles not grouped in rows shall be taken 
midway between the face of the column and the perimeter of the 
base of the frustum described in Section 138. 



Formula. 



Working 
Stress. 



Bond in 
Footings. 



(34) 



E. Bond. 

140. Bond between concrete and reinforcement bars in reinforced 
concrete beams and slabs shall be computed by the formula, 

V 

u = — 

Xojd 

141. Unless otherwise specified, the reinforcement shall be so 
proportioned that the bond stress between the metal and the concrete 
shall not exceed the following: 

(a) Plain bars, 

. w = 0.04/', (35) 

(b) Deformed bars, meeting the requirements of Section 23, 

^ = 0.05 /^ '. (36) 

142. The bond stress on a section of a footing shall be computed 
by Formula 34. Only the bars counted as effective in bending shall 



On Concrete and Reinforced Concrete. 45 

be considered in computing the number of bars crossing a section. 
The bond stress computed in this manner on sections at the face of 
the column or outside the column shall not exceed the value speci- 
fied in Section 141. Special investigation shall be made of bond 
stresses in footings with stepped or sloping upper surface; maximum 
stresses may occur at sections near the edges of the footings. 

143. The permissible bond stress given by Formulas 35 and 36 Reinforce- 
for footings and similar members where reinforcement is required in ™^More^^° 
more than one direction shall be reduced as follows : Directions. 

(a) For two-way reinforcement, 25 per cent; 

(b) For each additional direction, 10 per cent. 

144. The bond stresses for bars adequately anchored at both ends Anchored 
by hooks or otherwise, as provided in Section 130, may be ij times 
the values specified in Section 141. Hooks in footings shall be effec- 
tively positioned to insure that they engage a mass of concrete above 
the plane of the reinforcement. 



Bars. 



Flat Slabs. 



145. The symbols used in Formulas 37 to 42 are defined in Moments in 
Section 107 except as indicated in Sections 145, 148 and 158. In flat p^'aneis! 
slabs in which the ratio of reinforcement for negative moment in the 
column strip is not greater than 0.01 , the numerical sum of the positive 
and negative moments in the direction of either side of the panel shall 
be taken as not less than 

Mo = 0.09 Wl (l---)' (37) 

where Mo = sum of positive and negative bending moments in either 
rectangular direction at the principal design sections 
of a panel of a flat slab; 

c '-- base diameter of the largest right circular cone, which 
lies entirely wathin the column (including the capital) 
whose vertex angle is 90 deg. and whose base is 1^ in. 
below the bottom of the slab or the bottom of the 
dropped panel (see Fig. 14); 

/ = span length"^ of flat slab, center to center of columns in 

1 The requirements for flat slabs in Sections 145 to 162, inclusive, apply to two-way and four-way 
systems of reinforcement. The Committee is not prepared at this time to submit requirements 
covering other types of flat slabs. 

2 The colum.n strip and the middle strip to be used when considering moments in the direction of 
the dimension I are located and dimensioned as shown in Fig. 15. The dimension /i docs not always 
represent the short length of the panel. When moments in the direction of the shorter panel length 
are considered, the dimensions I and h are to be interchanged and the strips corresponding to those 
shown in Fig. 15 but extending in the direction of the shorter panel length are to be considered. 



46 



Progress Report of Joint Committee 



the rectangular direction in which moments are con- 
sidered; and 
W = total dead and Hve load uniformly distributed over a 
single panel area. 
146. The principal design sections for critical moments in flat 
slabs subjected to uniform load shall be taken as follows : 

(a) Negative moment in middle strip : extending in a rectangular 
direction from a point on the edge of panel /i/4 from column center 
a distance li/2 toward the center of adjacent column on the same 
panel edge. 

(b) Negative moment in column strip : extending in a rectangular 
direction along the edge of the panel from a point Zi /4 from the center 



Table III. — Momen-ts to be Used in Design of Flat Slabs. 


Strip. 


Flat Slabs without 
Dropped Panels. 


Flat Slabs with 
Dropped Panels. 




Negative. 


Positive. 


Negative. 


Positive. 



Slabs with 2-way 


Reinforcement. 






Column strip 


0.23 Mo 
0.46 Mo 
0.16 Mo 


0.11 Mc 
0.22 Mo 
0.16 Mo 


0.25 Mo 
0.50 Mo 
0.15 Mo 


0.10 Mo 


2 Column strips • 

Middle sirip 


0.20 Mo 
0.15 Mo 



Slabs with 4-wat Reinforcement. 



Column strip. . . 
2 Column strips. 
Middle strip. . . . 



0.25 Mo 


0.10 Mo 


0.27 Mo 


0.50 Mo 


0.20 Mo 


0.54 Mo 


0.10 Mo 


0.20 Mo 


0.08 Mo 



0.095 Mo 
0.190 Mo 
0.190 Mo 



of a column to a point c/2 from the center of the same column and 
thence one- quarter circumference about the column center to the 
adjacent edge of the panel. 

(c) Positive moment in middle strip: extending in a rectangular 
direction from the center of one edge of a middle strip a distance h/l 
to the center of the other edge of the same strip. 

(d) Positive moment in column strip : extending in a rectangular 
direction from the center of one edge of a column strip a distance /i/4 
to the center of the other edge of the same strip. 

147. The moments in the principal design sections shall be those 
given in Table III, except as follows: 

(a) The sum of the maximum negative moments in the two 
column strips may be greater or less than the values given in Table III, 
by not more than 0.03 Mo. 



On Concrete and Reineorced Concrete. 47 

(b) The maximum negative moment and the maximum positive 
moments in the middle strip and the sum of the maximum positive 
moments in the two column strips may each be greater or less than 
the values given in Table III, by not more than 0.01 Mo. 

148. The total thickness,^ /i, of the dropped panel in inches, w oi Thickness of 
the slab if a dropped panel is not used, shall be not less than: Flat Slabs 

Panels. 



/i = 0.0382 (l-1.44-)/\W^ +li (38)-' 

where R = ratio of negative moment in the two column strips to Mo, 
and w' = uniformly distributed dead and live load per unit of 
area of floor. 

For slabs with dropped panels the total thickness^ in inches at 
points away from the dropped panel shall be not less than : 

/2 = 0.02/ vV+1 (39) 

The slab thickness ti or 4 shall in no case be less than //32 for floor 
slabs, and not less than //40 for roof slabs. In determining minimum 
thickness by Formulas 38 and 39, the value of / shall be the panel 
length center to center of the columns, on long side of panel, h shall 
be the panel length on the short side of the panel, and bi shall be the 
width or diameter of dropped panel in the direction of h except that 
in a slab without dropped panel ^i shall be 0,5 /i. 

149. The dropped panel shall have a length or diameter in each Minimum 
rec tan ovular direction of not less than one- third the panel length in ^^^^nsions 

11?. 11.1 '^ of Dropped 

that direction, and a thickness not greater than 1.5 tz. Panels. 

150. In wall panels and other panels in which the slab is discon- Waii and 
tinuous at the edge of the panel, the maximum negative moment one ?^^^, 
panel length away from the discontinuous edge and the maximum Panels, 
positive moment between shall be taken as follows: 

(a) Column strip perpendicular to the wall or discontinuous edge, 

15 per cent greater than that given in Table III. 

(b) Middle strip perpendicular to wall or discontinuous edge, 

30 per cent greater than that given in Table III. 

In these strips the bars used for positive moments perpendicular 
to the discontinuous edge shall extend to the exterior edge of the 
panel at which the slab is discontinuous. 

151. In panels having a marginal beam on one edge or on each Panels with 

Wall Beams. 



1 The thickness will be in inches regardless of whether I and w' are in feet and pounds per square 
foot or in inches and pounds per square inch. 

* The values of R used in this formula are the coefficients of Mn for negative moment in tht- 
column strip in Table III. • 



48 



Progress Report of Joint Committee 



Discontinuous 
Panels. 



Flat Slabs 
on Bearing 
Walls. 



Point of 
Inflection. 



Reinforce- 
ment. 



Arrangement 
of Reinforce- 
ment. 



of two adjacent edges, the beam shall be designed to carry the load 
superimposed directly upon it. If the beam has a depth greater than 
the thickness of the dropped panel into which it frames, the beam 
shall be designed to carry, in addition to the load superimposed upon 
it, at least one-fourth of the distributed load for which the adjacent 
panel or panels are designed, and each column strip adjacent to and 
parallel with the beam shall be designed to resist a moment at least 
one-half as great as that specified in Table III for a column strip. ^ 
If the beam used has a depth less than the thickness of the dropped 
panel into which it frames, each column strip adjacent to and parallel 
with the beam shall be designed to resist the moments specified in 
Table III for a column strip. Where there are beams on two opposite 
edges of the panel, the slab and the beam shall be designed as though 
all the load was carried to the beam. 

152. The negative moments on sections at and parallel to the 
wall, or discontinuous edge of an interior panel, shall be determined 
by the conditions of restraint.^ 

153. Where there is a beam or a bearing wall on the center line 
of columns in the interior portion of a continuous fiat slab, the negative 
moment at the beam or wall line in the middle strip perpendicular to 
the beam or wall shall be taken as 30 per cent greater than the moment 
specified in Table III for a column strip. The column strip adjacent 
to and lying on either side of the beam or wall shall be designed to 
resist a moment at least one-half of that specified in Table III for 
a column strip. 

154. The point of inflection in any line parallel to a panel edge 
in interior panels of symmetrical slabs without dropped panels shall 
be assumed to be at a distance from the center of the span equal to -^ 
of the distance between the two sections of critical negative moment 
at opposite ends of the line; for slabs having dropped panels, the 
coefficient shall be J. 

155. The reinforcement bars which cross any section and which 
fulfill the requirements given in Section 156 may be considered as 
effective in resisting the moment at the section. The sectional area 
of a bar multiplied by the cosine of the angle between the direction 
of the axis of the bar and any other direction may be considered effec- 
tive as reinforcement in that direction. 

156. The design shall include adequate provision for securing the 
reinforcement in place so as to take not only the critical moments but 

1 In wall columns, brackets are sometimes substituted for capitals or other changes are made in 
the design of the capital. Attention is directed to the necessity for taking into account the change 
in the value of c in the moment formula for such cases. 

2 The committee is not prepared to make a more definite recommendation at this time. 



On Concrete and Reinforced Concrete. 49 

the moments at intermediate sections. All bars in rectangular or diag- 
onal directions shall extend on each side of a section of critical moment, 
either positive or negative, to points at least 20 diameters beyond the 
point of inflection as specified in Section 154. In addition to this 
provision, bars in diagonal directions used as reinforcement for negative 
moment shall extend on each side of a line drawn through the column 
center at right angles to the direction of the band at least a distance ' 
of 0.35 of the panel length, and bars in diagonal directions used as 
reinforcement for positive moment shall extend on each side of a 
diagonal through the center of the panel at least a distance equal to 
0.35 of the panel length; no splice by lapping shall be permitted at or 
near regions of maximum stress except as just described. At least 
two-thirds of all bars in each direction shall be of such length and shall 
be so placed as to provide reinforcement at two sections of critical 
negative moment and at the intermediate section of critical positive 
moment. Continuous bars shall not all be bent up at the same point 
of their length, but the zone in which this beni^ing occurs shall extend 
on each side of the assumed point of inflection, and shall cover a 
width of at least yz of the panel length. Mere sagging of the bars 
shall not be permitted. In four- way reinforcement the position of 
the bars in both diagonal and rectangular directions may be considered Reinforce- 
ir determining whether the width of zone of bending is sufficient. ment at 

c' ^ o Construction 

157. See Section 73. joints. 

158. The following formula shall be used in computing the XensUe 
tensile stress /" in the reinforcement in flat slabs ; the stress so com- S**".®^/ ^" 

- ^ . . . ' . Remforce- 

puted shall not at any of. the prmcipal design sections exceed the ment. 
values specified in Section 205 : 

/. = ^^ .(40) 

where i?Afo = moment specified in Section 147 for two column strips or 
for one middle strip; and 
i4^ = effective cross-sectional area of the reinforcement which 
crosses any of the principal design sections and which 
meets the requirements of Section 156. 

159. The following formulas shall be used in computing maximum Compressive 
compressive stress in the concrete in flat slabs; and the stress so com- l*'^.^^^ ^° _ 
puted shall not exceed 0.4/'^: ment. 

(a) Compression due to negative moment, i^ilfo, in the two column 
strips, 

^-W'(— t) '-' 



50 



Progress Report of Joint Committee 

(b) Compression due to positive moment, RMq, in the two column 
strips or negative or positive moment in the middle strip, 



fc 



6 RM, 

kjhd^ 



(42) 



160. See Section 136. 

161. The moment coefficients, moment distribution and slab 
thicknesses specified herein are for slabs which have three or more 
rows of panels in each direction, and in which the panels are approxi- 
mately uniform in size. For structures having a width of one or 
two panels, and also for slabs having panels of markedly different 
sizes, an analysis shall be made of the moments developed in both 
slab and columns, and the values given herein modified accordingly. 
Slabs with paneled ceihng or with depressed paneling in the floor shall 
be considered as coming under the requirements herein given. 

162. See Section 173. 



G. Reinforced Concrete Columns. 

163. The provisions in the following sections for the carrying 
capacity of reinforced columns are based on the assumption of a short 
column. Where the unsupported length is greater than 40 times the 
least radius of gyration (40 R), the carrying capacity of the column 
shall be determined by Formula 48 for slender columns. Principal 
columns in buildings shall have a width of not less than 12 in. Posts 
that are not continuous from story to story shall have a width of 
not less than 6 in. 

164. The unsupported length of a column in flat slab construction 
shall be taken as the clear distance between the under side of the 
capital and the top of the floor slab below. For beam-and-slab con- 
struction the unsupported length of a column shall be taken as the 
clear distance between the under side of the shallowest beam 
framing into it and the top of the floor slab below; where beams run 
in one direction only the clear distance between floor slabs shall be 
used. For columns supported laterally by struts or beams only, two 
struts shall be considered an adequate support, provided the angle 
between the two planes formed by the axis of the column with the 
axis of each strut is not less than 75 deg. nor more than 105 deg. 
The unsupported length for this condition shall be considered the 
clear distance between struts. When haunches are used at the 
junction of beams or struts with columns, the clear distance between 
supports may be considered as reduced by two-thirds of the depth of 
the haunch. 



On Concrete and Reinforced Concrete. 51 

165. The symbols used in Formulas 43 to 50 are detined in safe Load 
Section 107, except as indicated in Sections 165, 167, 170, 172, 180 on Spiral 
and 188. The safe axial load on columns reinforced with longitudinal 

bars and closely spaced spirals enclosing a circular core shall be deter- 
mined by Ihc following formula: 

• P = A,J\ + ul\ pA (43) 

where 

A = area of the concrete core enclosed within the spiral; 

P = total safe axial load on column whose h/R is less than 40; 

p = ratio of effective area of longitudinal reinforcement to area 

of the concrete core; and 
A^ = A {l— p) =net area of concrete core. 
The allowable value of /^ for use in this type of column shall be deter- 
mined by the following formula : 

;; = 300 + (0A0+4p)f\ (44) 

The longitudinal reinforcement shall consist of at least six bars of 
minimum diameter of ^ in., and its eft'ective cross-sectional area shall 
not be less than 1 per cent nor more than 5 per cent of that of the 
enclosed core. 

166. The spiral reinforcement shall be not less in amount than Spiral Rein- 
one-fourth the volume of the longitudinal reinforcement. It shall °'"^^"^®^*- 
consist of evenly spaced continuous spirals held firmly in place and 

true to Kne by at least three vertical spacer bars. The spacing of the 
spirals shall be not greater than one-sixth of the diameter of the core 
and in no case more than 3 in. The lateral reinforcement shall meet 
the requirements of the Tentative Specifications for Cold-Drawn 
Steel Wire for Concrete Reinforcement. (Appendix 7.) Reinforce- 
ment shall be protected every\vhere by a covering of concrete cast 
monolithic with the core, w^hich shall have a minimum thickness of 
l| in. in square columns and 2 in. in round or octagonal columns. 

167. The safe axial load on columns reinforced with longitudinal Safe Load 
bars and separate lateral ties shall be determined by the following ^hh Latera^i 
formula : Ties. 

P = A/f.+Asiif, (45) 

where ^'^ = net area of concrete in the column (total column area minus 
steel area) ; and 
^5 = effective cross-sectional area of longitudinal reinforcement. 
The value of /^ for this type of column shall not exceed 0.20 f\. 
The amount of longitudinal reinforcement considered in the calcula- 
tions shall be not more than 2 per cent nor less than 0.5 per cent of 



52 



Progress Report or Joint Committee 



Lateral Ties. 



Bending 
Stress in 
Columns. 



Composite 
Columns. 



the total area of the column. The longitudinal reinforcement shall 
consist of not less than 4 bars of minimum diameter of I in., placed 
with clear distance from the face of the column not less than 2 in. 

168. Lateral ties shall be not less than J in. in diameter, spaced 
not farther than 8 in. apart. 

169. Reinforced concrete columns subjected to bending stresses 
shall be treated as follows : 

(a) Spiral column. — The compressive unit stress on the concrete 
within the core area under combined axial load and bending shall not 
exceed by more than 20 per cent the value given for axial load by 
Formula 40. 

{h) Columns with Lateral Ties. — Additional longitudinal rein- 
forcement not to exceed 2 per cent shall be used if required and the 
compressive unit stress on the concrete under combined axial load and 
bending may be increased to 0.30 Z^. 

Tension due to bending in the longitudinal reinforcement shall 
not exceed 16,000 lb. per sq. in. 

170. The safe carrying capacity of composite columns in which 
a structural steel or cast-iron column is thoroughly encased in a spirally 
reinforced concrete core shall be based on a certain unit stress for the 
steel or cast-iron core plus a unit stress of 0.25 f\ on the area within 
the spiral core. The unit compressive stress on the steel section shall 
be determined by the formula: 

/, = 18,000-70 h/R (46) 

but shall not exceed 16,000 lb. per sq. in. The unit stress on the 
cast-iron section shall be determined by the formula: 

/, - 12,000-60 V^ (47) 

but shall not exceed 10,000 lb. per sq. in. In Formulas 46 and 47, 
/^ = compressive unit stress in metal core, and i?= least radius of 
gyration of the steel or cast-iron section. 

The diameter of the cast-iron section shall not exceed one-half 
of the diameter of the core within the spiral. The spiral reinforce- 
ment shall be not less than 0.5 per cent of the volume of the core 
within the spiral and shall conform in quality, spacing and other 
requirements to the provisions for spirals in reinforced concrete 
columns. Ample sections of concrete and continuity of reinforcement 
shall be provided at the junction with beams or girders. The area 
of the concrete between the spiral and the metal core shall be not less 
than that required to carry the total floor load of the story above on 
the basis of a stress in the concrete of 0.35/'^, unless special brackets 



On Concret]: and Reinforcm^d Concrete. 53 

are arranged on the metal core to receive directly the beam cr slalj 
loads. 

171. The safe load on a structural steel column of a section which structural 
fully encloses or encases an area of concrete, and which is protected columns, 
by an outside shell of concrete at least 3 in. thick, shall be computed 

in the same way as in the columns described in Section 170, allowing 
0.25 /^ on the area of the concrete enclosed by the steel section. The 
outside shell shall be reinforced by w^re mesh cr hoops weighing not less 
than 0.2 lb. per sq. ft. of surface of the core and with a maximum 
spacing of strands or hoops of 6 in. Special brackets shall be used 
to receive the entire floor load at each story. The working stress in 
steel columns shall be calculated by Formula 46, but shall not exceed 
16,000 lb. per sq. in. 

172. The permissible working unit stress on the core in axially Long 
loaded columns which have a length greater than 40 times the least °'"™°^- 
radius of gyration of the column core (40 R) shall be determined by 

the formula : 

^^ l.-33---^ (48) 

r uoR . 

where P' = total safe ax!al load en long cclumn; 

P = total safe axial load on column cf the same section whose 
h/ R is less than 40, determined as in Section 167; and 
R = least radius of gyration of column core. 

173. The bending moments in interior and exterior columns shall Bending 
be determined on the basis cf loading conditions and end restraint, ^i^^s^ ^^ 
and shall be provided for in the design. V The recognized standard 
methods shall be followed in calculating the stresses due to combined 

axial load and bending. 

H. Footings. 

174. Various types of reinforced concrete footings are in use Types. 
depending on conditions. The fundamental principles of the design 

of reinforced concrete will generally apply to footings as to other 
structural members. The requirements for flexure and shear in 
Sections 112 to 139, inclusive, shall govern the design of footings, 
except as hereinafter provided. 

175. The upward reaction per unit of area on the footing shall Distribution 
be taken as the column load divided by the area of base of the footing. °^ Pressure. 

176. Footings carried on piles shall be treated in the same man- Pile Footing, 
ner as those bearing directly on the soil, except that the reaction shall 

1 The Committee is not prepared to make more definite recommendations at this time. 



54 



Progress Report of Joint Committee 



Sloped 
Footing. 



Stepped 
Footing. 



Critical 
Section for 
Bending. 



Square 
Column on 
Square 
Footing. 



be considered as a series of concentrated loads applied at the pile 
centers. 

177. Footings in which the depth has been determined by the 
requirements for shear as specified in Section 137 may be sloped 
between the critical section and the edge of the footing, provided that 
the shear on no section outside the critical section exceeds the value 
specified, and provided further that the thickness of the footing above 
the reinforcement at the edge shall not be less than 6 in. for footings 
on soil nor less than 12 in. for footings on piles. 

178. The top of the footing may be stepped instead of sloped, 
provided that the steps are so placed that the footing will have at all 
sections a depth at least as great as that required for a sloping top. 
Stepped footings shall be cast monoHthically. 

179. In a concrete footing which supports a concrete column or 
pedestal, the critical section for bending shall be taken at the face of 
the column or pedestal. Where steel or cast-iron bases are used, the 
moment in the footing shall be calculated at the edge .of the base and 
at the center. In calculating this moment, the column or pedestal 
load shall be assumed as uniformly distributed over its base. 

180. For a square footing supporting a concentric square column, 
the bending moment at the critical section is that produced by the 
upward pressure on the trapezoid bounded by one face of the column, 
the corresponding outside edge of the footing, and the portions of the 
two diagonals. The center of application of the reaction on the two 
corner triangles of this trapezoid shall be taken at a distance from 
the face of the column equal to 0.6 of the projection of the footing. 
The center of the application of the reaction on the rectangular por- 
tion of the trapezoid shall be taken at its center of gravity. This 
gives a bending moment expressed by the formula : 



M 



w 



(a+1.2 c)c' 



(49) 



Round 
Column on 
Square 
Footing. 



where M = bending moment at critical section of footing; 
a = width of face of column or pedestal; 
c = projection of footing from face of column; and 
w = upward reaction per unit of area of base of footing. 

(For typical footing designs, see Figs. 16 to 18.) 

181. Square footings supporting a round or octagonal column 
shall be treated in the same manner as for a square column, using for 
the distance a the side of a square having an area equal to the area 
enclosed within the perimeter of the column. 



On Concrete and Reinforced Concrete. 55 

182. The reinforcement necessary to resist the bending moment Reinforce- 
in each direction in the footing shall be determined as for a reinforced ™®^*' 
concrete beam; the effective depth of the footing shall be the depth 

from the top to the plane of the reinforcement. The required area of 
reinforcement thus calculated shall be spaced uniformly across the 
footing, unless the footing width is greater than the side of the column 
or pedestal plus twice the effective depth of the footing, in which case 
the width over which the reinforcement is spread, may be increased 
to include one-half the remaining width of the footing. In order that 
no considerable area of the footing shall remain unreinforced, addi- 
tional bars shall be placed outside of the width specified, but such 
bars shall not be considered as effective in resisting the calculated 
bending moment. For the extra bars a spacing double that used for 
the reinforcement within the effective belt may be used. 

183. The extreme fiber stress in compression in the concrete shall Concrete 
be kept within the limits specified in Section 198. The extreme fiber 
stress in sloped or stepped footings shall be based on the exact shape 

of the section for a width not greater than that assumed effective for 
reinforcement. 

184. Rectangular or irregular-shaped footings shall be calculated irregular 
by dividing the footings into rectangles or trapezoids tributary to the °^ ^^^" 
sides of the column, using the distance to the actual center of gravity 

of the area as the moment arm of the upward forces. Outstanding 
portions of combined footings shall be treated in the same manner. 
Other portions of combined footings shall be designed as beams or slabs. 

185. See Sections 137 to 139. s^e^s^s^ 

186. See Sections 142 to 144. Bond 

187. The compressive stress in longitudinal reinforcement in stresses. 
columns or pedestals shall be transferred to the footing by one of the stress from 

following methods : Column Rein^ 

° . . forcement. 

(a) By metal distributmg bases havmg a sufficient area and 
thickness to transmit safely the load from the longitudinal reinforce- 
ment in compression and bending. The bases shall be accurately set 
and provided with a full bearing on the footing. 

(b) By dowels, at least one for each bar and of total sectional 
area not less than the area of the longitudinal column reinforcement. 
The dowels shall project into the columns or into the pedestal or 
footing a distance not less than 50 times the diameter of the column 
bars. 

188. The allowable compressive unit stress on the gross area of a Pedestals 
concentrically loaded pedestal without reinforcement shall not exceed Reinforce- 
0.25 f\. If the column resting on such a pedestal is provided with ment. 



56 



Progress Report of Joint Committe"" 



Pedestals 
with Rein- 
forcement. 



Permissible 
Load at Top 
of Footings. 



Pedestal 
Footings. 



distributing bases for the longitudinal reinforcement, the permissible 
compressive unit stress under the column core shall be determined by 
the following formula: 



r„ = 0.25 



''■% 



(50) 



where ta — permissible working stress over the loaded area; 
A = total net area of the top of pedestal; and 
A^ = loaded area of pedestal. 

189. Where the permissible load at the top of a pedestal, deter- 
mined by Formula 50, is less than the column load to be supported, 
dowels shall be used as specified in Section 187. If the height of the 
pedestal is not sufficient to give the required embedment to the dowels, 
they shall extend into the footing to a point 50 diameters below the 
top of the pedestal for plain bars and 40 diameters for deformed bars. 
If the column load divided by the cross-section of the pedestal exceeds 
0.25 /^c the pedestal shall be considered as a section of a column and 
spiral reinforcement shall be provided accordingly. 

190. Where distributing bases are used for transferring the stress 
from column reinforcement directly to the footing, the permissible 
compressive unit stress shall be determined by Formula 50. This 
formula may be applied by using A as the area of the top horizontal 
surface of the footing or with the following modifications : 

(a) In footings with sloping or stepped top in which a plane, 
drawn from the edge of the base of the column so that it makes the 
greatest possible angle with the vertical but remains entirely within 
the footing, has a slope with the horizontal not greater than 0.5, the 
total bearing area of the footing may be used for A . 

(b) In footings in which the slope of the plane referred to is 
greater than 0.5 but not greater than 2.0, the permissible compressive 
unit stress at the top shall be determined by direct proportion, in 
terms of the slope, between the value found for a slope of 0.5 and the 
value of 0.25 f\ for a slope of 2.0. For a slope of 2.0 or greater the 
compressive unit stress at the top shall not exceed 0.25 f'^- 

(For typical footing designs, see Figs. 16 and 18.) 

191. Pedestal footings may be designed as pedestals, that is, 
without reinforcement other than that required to transmit the 
column load, except that when supported directly on driven piles, a 
mat of reinforcing bars consisting of not less than 0.20 sq. in. per foot 
of width in each direction shall be placed 3 in. above the top of the 
piles. The height of a pedestal footing shall be not greater than 
4 times the average width. 



On Concrete and Reinforced Concrete. 57 

/. Reinforced Concrete Retaining Walls. 

192. Reinforced concrete retaining walls may be of the following Types of Re- 

taining Walls. 
types : 

{a) Cantilever; 

{h) Counterforted ; 

(c) Buttressed; 

{d) Cellular. 

193. Reinforced concrete retaining walls shall be designed' for Loads and 
the loads and reactions, and shall be so proportioned that the per- ^^* tresses, 
missible unit stresses specified in Sections 196 to 208 are not exceeded. 

The heels of cantilever, counterforted and buttressed retaining walls 
shall be proportioned for the maximum resultant vertical loads to 
which they will be subjected, but the sections shall be such that the 
normal permissible unit stresses will not be increased by more than 
50 per cent when the reaction from the foundation bed is neglected. 

194. The following principles shall be followed in the design of Details of 
reinforced concrete retaining walls : ^^^gn. 

(a) The unsupported toe and heel of the base slabs shall be con- 
sidered as cantilever beams fixed at the edge of the support. 

(b) The vertical section of a cantilever wall shall be considered as 
a cantilever beam fixed at the top of the base. 

(c) The vertical sections of counterforted and buttressed walls 
and parts of base slabs supported by the counterforts or buttresses 
shall be designed in accordance with the requirements specified herein 
for the continuous slab. 

{d) The exposed faces of walls without buttresses shall preferably 
be given a batter of not less than | in. in 12 in. 

(e) Counterforts shall be designed in accordance with the require- 
ments specified for T-beams. Stirrups shall be provided in the 
counterforts to take the reaction from. these spans when the tension 
reinforcement of the face walls and heels of bases is designed to span 
between the counterforts. Stirrups shall be anchored as near the 
exposed faces of the face walls, and as near the lower face of the bases, 
as practicable. 

(/) Buttresses shall be designed in accordance with the require- 
ments specified for rectangular beams. 

ig) The shearing stress at the junction of the base with counter- 

» In proportioning retaining walls consideration shall be given to the following: 

(a) Maximum bearing pressure of soil; 

(b) Uniformity of distribution of foundation pressure on yielding soils; 

(c) Stability against sliding; 

(d) Minor increase of the horizontal forces may seriously affect (a) and (fe). 



58 Progress Report of Joint Committee 

forts or buttresses shall not exceed the values specified in Sections 
120 to 135. 

Qi) Horizontal metal reinforcement shall be well distributed and 
of such form as to develop a high bond resistance. At least 0.25 sq. 
in. of horizontal metal reinforcement for each foot of height shall be 
provided near exposed surfaces not otherwise reinforced, to resist the 
formation of temperature and shrinkage cracks. 

{i) Provision for temperature changes shall be made by grooved 
lock joints spaced not over 60 ft. apart. 

{j) Counterforts and buttresses, where used, shall be located 
under all points of concentrated loading, and at intermediate points 
spaced 8 to 12 ft. apart. 

{k) The walls shall be cast monolithically between expansion 
joints, unless construction joints made in accordance with Sections 69 
and 73 are provided. 
Drains. 195. Drains or "weep holes" not less than 4 in. in diameter and 

not more than 10 ft. apart, shall be provided. In counterforted walls 
there shall be at least one drain for each pocket formed by the coun- 
terforts. 

J . Floor Slabs Supported on Four Sides ? 

K. Shrinkage and Temperature Stresses} 
L. Summary of Working Stresses. 
Notation. 196. f^ = ultimate compressive strength of concrete at age of 28 days, 

based on tests of 6 by 12-in. or 8 by 16-in. cylinders made 
and tested in accordance with the Standard Methods of 
Making and Storing Specimens of Concrete in the Field 
(Appendix 14) and the Tentative Methods of Making 
Compression Tests of Concrete (Appendix 13). 

a. Maximum Direct Stresses in Concrete. 
Direct 197; (a) Columns whose length docs uot cxcccd 40 i?.' 

ompression. ^^^ With Spirals varies with amount of 

longitudinal reinforcement 

(2) Without spirals. . 0.20/, 

(6) Long columns see Section 172 

(c) Piers and Pedestals: 

(1) Without reinforcement 0.25/'^ 

(2) Special cases see Section 188 

Compression ^93 (^) Extreme fiber stress in flexure 0.40/' 

in Extreme /7\ -r^ ^i 1. r 

Fiber. \o) Extreme fiber stress adjacent to supports of con- 
tinuous beams 0.45/'^ 

» The Committee is not now ready to report on these subjects. 



On Concrete and Reinforced Concrete. 59 

199. Anchorage of reinforcement 0.50 f. Bearing 

^^^ KM . ^ Compression. 

200. All concrete members none Tension 

h. Maximum SJiearing Stresses in Concrete. 

201. (a) Longitudinal bars anchored 0.03/^ Beams 

{h) Longitudinal bars not anchored 0.02/, RetfoJc^'^ 

202. (a) Beams with stirrups see Sections 125 and 128 ment. 

{h) Beams with bars bent up in several planes, .see Section 125 Beams with 
{c) Beams with bars bent up in a single plane : ment. 

(1) Longitudinal bars anchored 0.12 f^ 

(2) Longitudinal bars not anchored 0.06 f^ 

203. (a) Shear at distance d from capital or dropped panel. . .0.03/', Fiat Slabs. 
(b) Other hmiting cases in flat slabs see Section 136 

204. (a) Longitudinal bars anchored 0.03/, Footings. 

(b) Longitudinal bars not anchored 0.02 f^ 

c. Maximum Stresses in Reinforcement. 

205. (a) Billet-steel bars : Tension in 

(1) Structural steel grade 16,000 lb. per sq. in. 

(2) Intermediate grade 18,000 '' 

(3) Hard grade 18,000 '' 

{b) Rail-steel bars 16,000 '' 

(c) Structural steel 16,000 '' 

(d) Cold-drawn steel wdre : 

(1) Spirals stress not calculated 

(2) Elsewhere 18,000 lb. per sq. in. 

206. (a) Bars same as Section 205 (a) and (b) Compression 

(b) Structural steel core of composite column . . 1 8,000 lb. per sq. in. , 

reduced for slenderness ratio 

(c) Structural steel column 16,000 lb. per sq. in., 

reduced for slenderness ratio 

207. Composite columns with spirals 10,000 lb. per sq. in. Compression 

in Cast Iron. 

d. Maximum Bond between Concrete and Steel. 

208. (a) Beams and slabs, plain bars 0.04/, Bond. 

{b) Beams and slabs, deformed bars 0.05/, 

, {c) Footings, plain bars, one-way 0.04/, 

{d) Footings, deformed bars, one-way 0.05/, 

(e) Footings, two-way reinforcement W or {d) reduced by 

25 per cent 
(/) Footings, each additional direction of 

reinforcement {c) or {d) reduced by 

10 per cent. 



60 Progress Report of Joint Committee 



Table IV. — Proportions^ for Concrete of Given Compressive Strength at 

28 Days. 

The table gives the proportions in which Portland cement and a wide range in 
sizes of fine and coarse aggregates should be mixed to obtain concrete of compressive 
strengths ranging from 1500 to 3000 lb. per sq. in. at 28 days. Proportions are 
given for concrete of four different consistencies. 

The purpose of the table is twofold : 

(1) To furnish a guide in the selection of mixtures to be used in preliminary 
investigations of the strength of concrete from given materials. 

(2) To indicate proportions which may be expected to produce concrete of a 
given strength under average conditions where control tests are not made. 

If the proportions to be used in the work are selected from the table without 
preliminary tests of the materials, and control tests are not made during the progress 
of the work, the mixtures in bold-face type shall be used. 

The use of this table as a guide in the selection of concrete mixtures is based on 
the following : 

(1) Concrete shall be plastic; 

(2) Aggregates shall be clean and structurally sound; 

(3) Aggregates shall be graded between the sizes indicated; 

(4) Cement shall conform to the requirements of the Standard Specifications 
and Tests for Portland Cement (Serial Designation : C 9-2 1 ) of the American Society 
for Testing Materials. (Appendix 3.) - 

The plasticity of the concrete shall be determined by the slump test carried 
out in accordance with the Tentative Specifications for Workability of Concrete for 
Concrete Pavements (Serial Designation: D 62-20 T) of the American Society for 
Testing Materials. (Appendix 12.) 

Apply the following rules in determining the size assigned to a given aggregate : 

(1) Not less than 15 per cent shall be retained between the sieve which is con- 
sidered the maximum size^ and the next smaller sieve. 

(2) Not more than 15 per cent of a coarse aggregate shall be finer than the sieve 
considered as the minimum size.^ 

(3) Only the sieve sizes given in the table shall be considered in applying rules 
(1) and (2). 

(4) Sieve analysis shall be made in accordance with the Tentative Method of 
Test for Sieve Analysis of Aggregates for Concrete (Serial Designation: C 41-21 T) 
of the American Society for Testing Materials. (Appendix 9.) 

Proportions may be interpolated for concrete strengths, aggregate sizes and 
consistencies not covered by the table or determined by test. 



1 Based on the 28-day compressive strengths of 6 by 12-in. cylinders, made and stored in 
accordance with the Tentative Methods of Making Compression Tests of Concrete (Serial Desig- 
nation: C 39-21 T) of the American Society for Testing Materials. (Appendix 13.) 

2 For example: a graded sand with 16 per cent retained on the No. 8 sieve would fall in the 
0-No. 4 size; if 14 per cent or less were retained, the sand would fall in the 0-No. 8 size. A coarse 
aggregate having 16 per cent coarser than 2-in. sieve would be considered as 3-in. aggregate. 



On Concrete and Reinforced Concrete. 



61 



Table IV. {Continued). — Proportions for 1500 lb. per sq. in. Concrete. 

Proportions are expressed by volume as follows: Portland Cement : Fine Aggregate : Coarse Aggregate. 
Thus 1 : 2.6 : 4.6indicates 1 part by volume of Portland cement, 2.6 parts by volume of fine aggregate and 1.0 
parts by vobimc of coarse aggregate. 



Size of Coarse 


Slump, 
in. 

\ to 1 






Size of Fine Aggregate. 




.\gKrcKate. 


O-No.28 


0-No 


14 


O-No.S 


O-No.4 


0-f in. 




1 


2.8 


1 : 3.2 


1 :3.8 


1 :4.4 


1 :5.1 


None < 


3 •• 4 


1 


2.4 


1 : 2.8 


1:3.3 


1 : 3.8 


1 :4.5 


6 •' 7 


1 


1.9 


1:2.2 


1 :2.6 


1 :3.0 


1 :3.6 


1 


8 "10 


1 


1.4 


1: 1.6 


1: 1.8 


1 : 2.1 


1:2.5 




\ to 1 


1 : 2.6 : 4.6 


1 : 2.9 : 4.3 


1:3.4:4.1 


1 : 3.9 : 3.6 


1 : 4.6 : 3.1 


No. 4 to * in < 


3 " 4 


1 : 2.3 : 4.0 


1 : 2.6 : 3.8 


1 : 2.9 : 3.6 


1 : 3.4 : 3.2 


1:4.1:2.8 


6 " 7 


1:1.8:3.4 


1 : 2.0 : 3.2 


1 : 2.3 : 3.1 


1 : 2.6 : 2.8 


1 : 3.1 : 2.5 




8 "lO 


1 : 1.1 : 2.5 


1 : 1.3 : 2.4 


1 : 1.5 : 2.4 


1 : 1.7 : 2.2 


1 : 2.1 : 2.0 


( 


\ to 1 


1 : 2.4 : 5.3 


1:2.7 


5.2 


1 : 3.1 : 5.0 


1 : 3.5 : 4.7 


1 : 4.3 : 4.3 


No. 4 to 1 in < 


3 " 4 


1 : 2.1 : 4.7 


1:2.4 


4.5 


1 : 2.7 : 4.4 


1:3.1:4.1 


1 : 3.7 : 3.7 


6 " 7 


1:1.6:3.9 


1 :1.8 


3.8 


1 : 2.1 : 3.7 


1 : 2.4 : 3.5 


1 : 2.9: 3.3 


1 


8 "10 


1: 1.1:2.9 


1: 1.2 


2.8 


1 : 1.4 : 2.8 


1: 1.6:2.7 


1 : 1.9 : 2.5 


[ 


\ to 1 


1 : 2.4 : 6.0 


1 : 2.7 : 5.9 


1 : 3.1 : 5.8 


1 : 3.5 : 5.4 


1 : 4.1 : 5.1 


No. 4 to U in ■ 


3 " 4 

6 " 7 


1 : 2.0 : 5.4 
1:1.6:4.4 


1 : 2.3 : 5.3 
1 : 1.8: 4.3 


1 : 2.7 : 5.2 
1 : 2.0 : 4.3 


1 : 3.0 : 5.0 
1 : 2.3 : 4.1 


1 : 3.5 : 4.6 
1 : 2.7 : 3.9 


• 


8 "10 


1 : 1.0 : 3.3 


1 : 1.1 : 3.2 


1 : 1.3 : 3.2 


1: 1.5:3.1 


1 : 1.8 : 2.9 


f 


\ to 1 


1 : 2.2 : 6.9 


1 : 2.4 : 6.8 


1 : 2.8 


6.8 


1 : 3.1 : 6.6 


1 : 3.7 : 6.4 


No. 4 to 2 in i 


3 " 4 
6 " 7 


1 : 1.8 : 6.2 
1 : 1.4:5.1 


1 : 2.0 : 6.1 
1:1.6:5.0 


1:2.4 
1 :1.8 


6.1 
5.0 


1 : 2.7 : 6.0 
1 : 2.0 : 5.0 


1:3.1:5.7 
1 : 2.4 : 4.8 


1 


8 "10 


1 • 0.9 : 3.8 


1: 1.0:3.8 


1 : 1.1 


3.8 


1 : 1.3 : 3.8 


1 : 1.5 : 3.7 


[ 


\ to 1 


1 : 2.8 : 5.2 


1:3.1:5.1 


1 : 3.6 : 4.8 


1 : 4.2 : 4.6 


1 : 4.8 : 4.1 


3 1 

ftolin 


3 " 4 
6 " 7 


1 : 2.4 : 4.5 
1:1.9:3.9 


1 : 2.6 : 4.5 
1 : 2.1 : 3.7 


1 : 3.1 : 4.3 
1:2.4:3.6 


1 : 3.6 : 4.0 
1 : 2.8 : 3.4 


1 : 4.1 : 3.6 
1 : 3.2 : 3.1 


1 


8 "10 


1 : 1.3 : 2.8 


1 : 1.4 : 2.8 


1 : 1.6:2.7 


1 : 1.9 : 2.6 


1 : 2.2 : 2.4 


f 


\ to 1 


1 : 2.8 : 5.8 


1 : 3.1 : 5.7 


1 : 3.5 : 5.5 


1 : 4.1 : 5.3 


1 : 4.7 : 4.9 


1 to 1^ in < 


3 " 4 
6 " 7 


1 : 2.4 : 5.2 
1 : 1.9: 4.3 


1 : 2.7 : 5.1 
1 : 2.1 : 4.2 


1:3.1:5.0 
1 : 2.4 : 4.2 


1 : 3.5 : 4.8 
1 : 2.7 : 4.0 


1 : 4.1 : 4.4 
1 : 3.1 : 3.7 


1 


8 "10 


1 : 1.2:3.2 


1 : 1.4 : 3.2 


1 : 1.6 : 3.1 


1 : 1.8 : 3.0 


1 : 2.1 : 2.9 


f 


\ to 1 


1 : 2.7 : 6.6 


1 : 3.0 : 6.6 


1 : 3.4 : 6.5 


1 : 3.9 : 6.4 


1 : 4.4 : 6.0 


f to 2 in < 


3 " 4 
6 " 7 


1 : 2.3 : 5.9 
1 : 1.8: 4.9 


1 : 2.6 : 5.9 
1 : 2.0 : 4.8 


1 : 2.9 : 5.8 
1 : 2.2 : 4.8 


1 : 3.3 : 5.6 
1 : 2.6 : 4.8 


1 : 3.7 : 5.5 




1 : 3.0 : 4.5 




8 "10 


1: 1.2:3.7 


1:1.3:3.7 


1:1.5:3.7 


1: 1.7:3.6 


1 : 1.9 : 3.5 


' 


\ to 1 


1 : 3.2 : 5.4 


1 : 3.6 : 5.3 


1:4.1:5.1 


1 : 4.7 : 4.8 


1 : 5.3 : 4.4 


1 to l^in \ 


3 " 4 
6 " 7 


1 : 2.8 : 4.8 
1 : 2.1 : 4.0 


1 : 3.2 : 4.8 
1 : 2.5 : 4.0 


1:3.6:4.6 
1 : 2.8 : 3.9 


1 : 4.0 : 4.4 
1 : 3.2 : 3.7 


1:4.6:4.0 




1 : 3.5 : 3.4 




8 "10 


1 : 1.5 : 3.0 


1 : 1.7 : 3.0 


1: 1.9: 2.9 


1 : 2.2 : 2.8 


1 : 2.5 : 2.7 




\ to 1 


1 : 3.2 : 6.2 


1 : 3.6 : 6.1 


1 : 4.0 : 6.0 


1 : 4.6 : 5.8 


1 : 5.2 : 5.4 


f to 2 in \ 


3 " 4 
6 " 7 


1 : 2.8 : 5.5 
1 : 2.1 : 4.5 


1:3.1:5.5 
1 : 2.4: 4.6 


1 : 3.5 : 5.4 
1 : 2.7 : 4.5 


1 : 3.9: 5.2 
1 : 3.1 : 4.4 


1 : 4.5 : 4.9 
1 : 3.5 : 4.1 




8 "10 


1 : 1.4 : 3.4 


1: 1.6:3.4 


1 : 1.8:3.4 


1 : 2.1 : 3.4 


1 : 2.4 : 3.3 


■ 


h to 1 


1:3.2:7.1 


1:3.6:7.1 


1 : 4.0 : 7.0 


1 : 4.6 : 6.9 


1 : 5.2 : 6.6 


f to3 in < 


3 " 4 
6 " 7 


1 : 2.7 : 6.3 
1 : 2.1 : 5.1 


1 : 3.0 : 6.3 
1 : 2.4 : 5.2 


1 : 3.4 : 6.3 
1 : 2.7 : 5.2 


1 : 4.0 : 6.2 
1 : 3.1 : 6.1 


1:4.5:5.9 




1 : 3.5 : 4.9 




8 "10 


1 : 1.4 : 3.8 


1 : 1.6:3.9 


1 : 1.8:3.9 


1 :2.1 :3.9 


1 : 2.4 : 3.8 



62 



Progress Report of Joint Committee 



Table IV. {Continued). — Proportions for 2000 lb. per sq. in. Concrete. 

Proportions are expressed by volume as follows: Portland Cement : Fine Aggregate : Coarse Aggregate. 
Thus 1 : 2.6 : 4.6 indicates 1 part by volume of Portland cement, 2.6 parts by volume of fine aggregate and 4.i 
parts by volume of coarse aggregate. 



Size of Coarse 


Slump, 
in. 




Size of Fine Aggregat 


e. 




Aggregate. 


- No. 28 


- No. 14 


- No. 8 


- No. 4 


0-f in. 




ito 1 


1:2.2 


1:2.6 


1:3.0 


1:3.5 


1 ; 4.1 


None < 


3 " 4 


1: 1.9 


1:2.2 


1:2.6 


1:3.0 


1:3.5 


6 " 7 


1:1.5 


1:1.7 


1:2.0 


1 :2.3 


1 :2.7 


. 


8 "10 


1:1.0 


1 :1.1 


1 :1.3 


1 : 1.6 


1 : 1.8 


f 


itol 


1 : 2.1 : 3.8 


1 : 2.3 : 3.7 


1 : 2.6 : 3.5 


1 : 3.0 : 3.1 


1 : 3.6 : 2.8 


No. 4 to |in < 


3 " 4 


1 : 1.7 : 3.3 


1 : 1.9 : 3.2 


1 : 2.2 : 3.1 


1 : 2.6 : 2.8 


1 : 3.0 : 2.4 


6 " 7 


1 :1.3i:2.7 


1 : 1.4: 2.6 


1 : 1.7: 2.5 


1 : 1.9: 2.3 


1 : 2.3 : 2.1 


I 


8 "10 


1 : 0.8 : 1.9 


1 : 0.9 : 1.9 


1: 1.0: 1.8 


1 : 1.2: 1.7 


1 : 1.5 : 1.6 


f 


\ to 1 


1 : 1.9 : 4.5 


1 : 2.2 : 4.3 


1 : 2.5 : 4.2 


1:2.8:3.9 


1 : 3.4 : 3.6 


No. 4 to 1 in ' 


3 '■ 4 


1 : 1.6 : 3.9 


' 1 : 1.8 : 3.8 


1 : 2.1 : 3.7 


1 : 2.4 : 3.5 


1 : 2.8 : 3.2 


6 " 7 


1 : 1.2: 3.1 


1 : 1.3: 3.1 


1 : 1.5: 3.0 


1 : 1.8: 2.9 


1 : 2.1 : 2.7 




8 "10 


1 : 0.7 : 2.2 


1 : 0.8 : 2.2 


1 : 1.0 : 2.3 


1 : 1.1 : 2.1 


1 : 1.3 : 2.0 


f 


f to 1 


1 : 1.9 : 5.0 


1 : 2.1 : 4.9 


1 : 2.4 : 4.9 


] : 2.7 : 4.6 


1 : 3.2 : 4.4 


No. 4 to if in I 


3 " 4 

6. " 7 


1 : 1.6 : 4.4 
1:1.1:3.5 


1 : 1.7 : 4.3 
1:1.3:3.5 


1 : 2.0 : 4.2 
1 : 1.4: 3.5 


1 : 2.4 : 4.0 
1 : 1.7: 3.4 


1 : 2.7 : 3.8 
1 : 2.0 : 3.2 


1 


8 "10 


1 : 0.7 : 2.5 


1 : 0.8 : 2.5 


1 : 0.9 : 2.5 


1 : 1.0 : 2.4 


1 : 1.2 : 2.3 


{ 


ito 1 


1 : 1.7 : 5.8 


1 : 1.9 : 5.7 


1 : 2.1 : 5.8 


1 : 2.4 : 5.6 


1 : 2.S : 5.5 


No. 4 to 2 in 1 


3 " 4 
6 " 7 


1 : 1.4 : 5.0 
1:1.0:4.1 


1 : 1.5 : 5.0 
1 :1.1 :4.1 


1 : 1.8 : 5.0 
1 : 1.2: 4.1 


1 : 2.0 : 4.9 
1 : 1.4: 4.1 


1 : 2.3 : 4.7 
1 : 1.7: 3.9 




8 "10 


1 : 0.6 : 2.9 


1 : 0.7 : 2.9 


1 : 0.7 : 3.0 


1 : 0.8 : 2.9 


1 : 1.0 : 2.9 




Itol 


1 : 2.2 : 4.4 


1 : 2.5 : 4.2 


1 : 2.8 : 4.1 


1 : 3.3 : 3.8 


1 : 3.8 : 3.4 


I to 1 in < 


3 ' 4 
6 " 7 


1 : 1.9 : 3.8 
1:1.4:3.1 


1 : 2.1 : 3.7 
1:1.5:3.0 


1 : 2.4 : 3.6 
1 : 1.8: 3.0 


1 : 2.8 : 3.4 
1 : 2.1 : 2.8 


1:3.2:3.1 
1 : 2.4 : 2.5 


1 


8 "10 


1 : 0.9 : 2.2 


1 : 1.0 : 2.2 


1 : 1.1 : 2.2 


1 : 1.3 : 2.0 


1 : 1.5 : 1.9 


f 


h to 1 


1 : 2.2 : 4.9 


1 : 2.5 : 4.8 


1 : 2.8 : 4.7 


1 : 3.2 : 4.6 


1 : 3.7 : 4.2 


ftollin 1 


3 " 4 
6 * 7 


1 : 1.9 : 4.3 
1 : 1.4: 3.5 


1 : 2.1 : 4.2 
1 : 1.5: 3.4 


1 : 2.4 : 4.1 
1 : 1.7: 3.4 


1 : 2.7 : 4.0 
1 : 2.Q : 3.3 


1 : 3.1 : 3.7 
1 : 2.3 : 3.1 


' 


8 "10 


1 : 0.9 : 2.5 


1 : 1.0 : 2.5 


1 : 1.1 : 2.4 


1 : 1.3 : 2.4 


1 : 1.5 : 2.3 




2 to 1 


1 : 2.1 : 5.6 


1 : 2.3 : 5.5 


1 : 2.6 : 5.5 


1 : 3.0 : 5.4 


1 : 3.5 : 5.1 


f to 2 in { 


3 " 4 
6 " 7 


1 : 1.7 : 4.8 
1:1.3:4.0 


1 : 2.0 : 4.8 
J: 1.4: 3.9 


1 : 2.2 : 4.8 
1 : 1.6: 3.9 


1 : 2.5 : 4.7 
1 : 1.8: 3.9 


1 : 2.9 : 4.4 




1 : 2.1 : 3.8 




8 "10 


1 : 0.8 : 2.9 


1 : 0.9 : 2.9 


1 : 1.0 : 2.9 


1 : 1.2 : 2.9 


1 : 1.3 : 2.8 


{ 


1 to 1 


1 : 2.6 : 4.5 


1 : 2.9 : 4.5 


1 : 3.3 : 4.4 


1 : 3.8 : 4.2 


1 : 4.3 : 3.9 


ftolfin.. 


3 " 4 

6 " 7 


1 : 2.2 : 3.9 
1:1.6:3.2 


1 : 2.5 : 3.9 
1:1.8:3.2 


1 : 2.8 : 3.8 
1 : 2.1 : 3.1 


1 : 3.2 : 3.6 
1 : 2.4 : 3.0 


1 : 3.6 : 3.3 




1 : 2.7 : 2.8 




8 "10 


1 : 1.0 : 2.3 


1 : 1.2 : 2.3 


1 : 1.4 : 2.2 


1 : 1.6 : 2.2 


1 : 1.8 : 2.1 


f 


f tol 


1 : 2.5 : 5.2 


1 : 2.8 : 5.2 


1 : 3.2 : 5.1 


1 : 3.6 : 5.0 


1 : 4.1 : 4.7 


f to 2 in '' 


3 " 4 
6 " 7 


1 : 2.1 : 4.5 
1:1.6:3.7 


1 : 2.4 :-4.5 
1:1.8:3.7 


1 : 2.7 : 4.4 
1 : 2.0 : 3.7 


1 : 3.1 : 4.3 
1 : 2.3 : 3.6 


1 : 3.5 : 4.0 
1 : 2.6 : 3.5 




8 "10 


1 : 1.0 : 2.6 


'l: 1.1:2.7 


1 : 1.3 : 2.6 


1 : 1.5 : 2.7 


1 : 1.7 : 2.6 




\ to 1 


1 : 2.5 : 6.0 


1 : 2.9 : 5.9 


1 : 3.2 : 5.9 


1 : 3.6 : 5.8 


1 : 4.1 : 5.6 


f to 3 in < 


3 " 4 
6 " 7 


1 : 2.1 : 5.1 
1 : 1.5: 4.1 


1 : 2.4 : 5.2 
1 : 1.7: 4.2 


1 : 2.7 : 5.2 
1 : 2.0 : 4.2 


1:3.1:5.1 
1 : 2.3 : 4.2 


1 : 3.5 : 4.9 
1 : 2.5 : 4.0 




8 "10 


1 : 1.0 : 2.9 


1 : 1.1 : 3.0 


1 : 1.3 : 3.0 


1 : 1.5 : 3.0 


1 : 1.7:3.0 



On Concrete and Reinforced Concrete. 



63 



Table IV. {Continued). — Proportions for 2500 lb. per sq. in. Concrete. 

Proportions are expressed by volume as follows : Portland Cement : Fine Aggregate : Coarse Aggregate. 
Thus 1 : 2.6 : 4.6 indicates 1 part by volume of Portland Cement, 2.6 parts by volume of fine aggregate and 4.i 
parts by volume of coarse aggregate 



Size of Coarse 
Aggregate. 



Nono. 



No. 4 to "4 in. 



No. 4 to 1 in. 



No. 4 to U in. 



No. 4 to 2 in. 



s" (o 1 in. 



i to 1^ in 



1 to 2 in. 





Slump, 




in. 


f 


Itol 


) 


3 " 4 


1 


6 " 7 


1 


8 "10 


■ 


Itol 




3 " 4 




6 " 7 


I 


8 "10 




itol 




3 " 4 




6 " 7 




8 "10 


f 


|to 1 


1 


3 ' 4 




6 " 7 




8 "10 




Itol 




3 " 4 




6 " 7 


I 


8 "10 




itol 




3 " 4 




6 " 7 




8 "10 


( 


itol 




3 " 4 




6 " 7 




8 "10 




Itol 




3 " 4 




6 " 7 


I 


8 "10 




itol 




3 " 4 




6 " 7 




8 "10 


f 


Itol 


J 


3 " 4 




6 " 7 




8 "10 




2 to 1 




3 " 4 


1 


6 " 7 


I 


8 "10 






-No 


.28 





-No 


. 14 




:1.8 






2.1 






: 1.5 






1.8 






:1.1 






:1.3 






•0.7 






0.8 






1.6 


3.2 




1.8 


3.1 




1.3 


2.8 




: 1.5 


2.7 




:1.0 


:2.2 




1.1 


2.2 




•0.5 


1.4 




0.6 


1.4 




1.5 


3.7 




1.7 


3.7 




1.2 


3.3 




1.4 


3.2 




:0.9 


2.6 




■1.0 


2.5 




0.5 


1.7 




0.6 


1.7 




1.4 


4.2 




1.6 


4.1 




1.2 


3.7 




1.3 


3.6 




:0.9 


2.9 




0.9 


2.8 




0.5 


1.9 




0.5 


1.9 




1.3 


4.9 




1.4 


4.8 




1.1 


4.3 




1.2 


4.2 




0.7 


3.3 




0.8 


3.3 




0.4 


2.2 




2.4 


2.2 




1.8 


3.7 




2.0 


3.6 




1.4 


3.2 




1.6 


3.1 




1.0 


2.5 




1.2 


2.5 




0.6 


1.6 




0.7 


1.6 




1.7 


4.1 




1.9 


4.1 




1.5 


3.6 




1.6 


3.6 




1.0 


2.9 




1.2 


2.8 




0.6 


1.9 




0.6 


1.9 




1.7 


4.7 




1.8 


4.7 




1.4 


4.1 




1.5 


4.1 




1.0 


3.2 




1.1 


3.2 




0.5 


2.1 




0.6 


2.1 




2.0 


3.8 




2.3 


3.8 




1.7 


3.3 




2.0 


3.3 




1.2 


2.6 




1.4- 


2.6 




0.7 


1.7 




0.8 


1.7 




2.0 


4.4 




2.2 


4.4 




1.7 


3.8 




1.9 


3.8 




1.2 


3.0 




1.4 


3.0 




0.7 


2.0 




0.8 


2.0 




2.0 


5.0 




2.2 


5.0 




1.7 


4.3 




1.9 


4.3 




1.2 


3.3 




1.4 


3.4 




0.7 


2.2 




0.8 


2.2 



Size of Fine Aggregate. 

- No. 8 - No. 4 



1:2.4 
1:2.1 



1 : 2.1 : 3.0 
1 : 1.7 : 2.6 
1 : 1.3: 2.1 

1 : 0.7 : 1.4 

1 : 2.0 : 3.5 
1: 1.6:3.1 
1 :1.1 :2.5 
1 : 0.6 : 1.7 



1 : 1.9 : 4.1 
1 : 1.5 : 3.6 
1 :1.1 :2.8 
1 : 0.6 : 1.9 



1 : 1.6 : 4.9 
1 : 1.3 : 4.3 
1 : 0.9 : 3.4 
1 : 0.5 : 2.2 

1 : 2.3 : 3.5 
1 : 1.9 : 2.9 
1:1.3:2.4 
1 : 0.8 : 1.6 

1 : 2.2 : 4.0 
1 : 1.8 : 3.5 
1 : 1.3: 2.8 

1 : 0.8 : 1.8 

1 : 2.1 : 4.7 
1: 1.7:4.1 
1 : 1.2: 3.2 
1 : 0.7 : 2.2 

1 : 2.6 : 3.7 
1 : 2.2 : 3.2 
1 : 1.6: 2.6 
1:0.9: 1.7 

1 : 2.5 : 4.3 
1:2.1 :3.8 
1:1.5:3.0 
1 : 0.9 : 2.0 

1 : 2.5 : 5.0 
1:2.1:4.3 
1 : 1.5: 3.4 
1 : 0.9 : 2.2 



1: 2.9 
1:2.4 
1 :1.8 
1: 1.1 

1 : 2.4 : 2.7 
1 : 2.0 : 2.4 
1 : 1.5: 2.0 
1 : 0.8 : 1.4 

1 : 2.2 : 3.4 
1 : 1.9 : 3.0 
1 : 1.3: 2.4 
1 : 0.7 : 1.6 

1 : 2.2 : 4.0 
1 : 1.8 : 3.5 
1 : 1.3: 2.8 
1 : 0.7 : 1.8 

1 : 1.9 : 4.8 
1 : 1.6 : 4.2 
1 1.1 :3.3 

1 : 0.6 : 2.2 

1 : 2.6 : 3.3 
1 : 2.2 : 2.9 
1 : 1.6: 2.3 

1 : 0.9 : 1.6 



1 : 2.5 : 3.9 
1: 2.1:3.4 
1 : 1.5: 2.7 

1 : 0.9 : 1.8 



1 : 2.4 : 4.6 
1 : 2.0 : 4.0 
1 : 1.4: 3.2 
1 :'0.8:2.2 

1 : 3.0 : 3.6 
1 : 2.5 : 3.2 
1 : 1.9: 2.5 
1 : 1.1: 1.7 

1 : 2.9 : 4.3 
1 : 2.5 : 3.7 
1:1.8:3.0 

1 : 1.0 : 2.0 

1 : 2.7 : 5.0 
1 : 2.4 : 4.3 
1 : 1.8: 3.4 
1 : 1.0 : 2.3 



3.3 
2.8 
2.1 

1.3 

2.9 : 2.4 

2.4 : 2.2 
1.8:1.8 
1.0: 1.3 

2.7:3.1 
2.2 : 2.7 
1.6:2.3 
0.9 : 1.5 

2.5 : .-l.S 

2.1 : 3.3 
1.5:2.6 
0.8 : 1.8 

2.2 : 4.7 
1.8:4.1 
1.2:3.3 
0.6 : 2.2 

3.0 : 2.9 
2.5 : 2.6 
1.8:2.2 
1.0: 1.5 

2.9 : 3.6 

2.3 : 3.2 
1.8:2.6 
1.0: 1.8 

2.7 : 4.4 

2.3 : 3.9 
1.6:3.1 
0.9 : 2.1 

3.4 : 3.3 
2.9 : 2.9 

2.1 : 2.3 
1.2: 1.6 

3.3 : 4.1 
2.8:3.6 
2.0 : 2.8 

1.2 : 2.0 

3.2 : 4.7 
2.7:4.1 
2.0 : 3.3 
1.2:2.3 



64 



Progress Report of Joint Committee 



Table IV. {Continued). — Proportions for 3000 lb. per sq. in. Concrete. 

Proportions are expressed by voliime as follows: Portland Cement : Fine Aggregate : Coarse Aggregate. 
Thud 1 : 2.6 : 4.6 indicates 1 part by volume of Portland Cement, 2.6 parts by volimie of fine aggregate and 4j 
parts by volume of coarse aggregate. 



Size of Coarse 


Slump, 
in. 


Size of Fine Aggregate. 


Aggregate. 


- No. 28 


- No. 14 


O-No.8 


- No. 4 


0-fin. 


f 


itol 


1: 1.5 


1 : 1.7 


1:2.0 


1:2.3 


1 : 2.7 


None < 


3 " 4 


1:1.2 


1: 1.4 


1:1.7 


1: 1.9 


1:2.3 


6 " 7 


1:0.9 


1:1.0 


1:1.2 


1:1.4 


1:1.6 




8 " 10 


1:0.5 


1:0.6 


1:0.7 


1:0.8 


1:0.9 


c 


Itol 


1 : 1.3 : 2.7 


1 : 1.5 : 2.6 


1 : 1.7 : 2.5 


1 : 1.9 : 2.4 


1 : 2.3 : 2.1 


No. 4 to fin < 


3 " 4 
6 '• 7 


1 : l.b : 2.3 
1 : 0.7: 1.7 


1 : 1.2 : 2.2 
1:0.8:1.7 


1 : 1.4 : 2.2 
1:0.9:1.7 


1 : 1.6 : 2.0 
1 :1.1 :1.6 


1 : 1.9 : 1.8 
1:1.3:1.4 


. 


8 " 10 


1 : 0.3 : 1.0 


1 : 0.4 : 1.0 


1 : 0.5 : 1.0 


1 : 0.5 : 1.0 


1 : 0.6 : 0.9 




itol 


1 : 1.2 : 3.1 


1 : 1.3 : 3.1 


1 : 1.5 : 3.0 


1 : 1.8 : 2.9 


1 : 2.1 : 2.7 


No. 4 to 1 in < 


3 " 4 


1 : 0.9 : 2.7 


1 : 1.1 : 2.6 


1 : 1.2 : 2.6 


1 : 1.4 : 2.5 


1 : 1.7 : 2.3 


6 •• 7 


1 : 0.6 : 2.0 


1 : 0.7 : 2.0 


1 : 0.8 : 2.0 


1:0.9:1.9 


1:1.1:1.8 


. 


8 "10 


1 : 0.3 : 1.2 


1 : 0.3 : 1.2 


1 : 0.4 : 1.2 


1 : 0.5 : 1.2 


1 : 0.6 : 1.2 




itol 


1 : 1.1 : 3.6 


1 : 1.2 : 3.5 


1 : 1.5 : 3.5 


1 : 1.7 : 3.4 


1 : 2.0 : 3.2 


No. 4 toll in < 


3 " 4 
6 " 7 


1 : 0.9 : 3.0 
1 : 0.6 : 2.2 


1 : 1.0 : 2.9 
1 : 0.7 : 2.2 


1 : 1.2 : 2.9 
1 : 0.3 : 2.2 


1 : 1.4 : 2.9 
1 : 0.9 : 2.2 


1 : 1.6 : 2.7 
1 : 1.1 : 2.1 


. 


8 "10 


1 : 0.3 : 1.4 


1 : 0.3 : 1.3 


1 : 0.4 : 1.4 


1 : 0.5 : 1.4 


1 : 0.5 : 1.3 




ito 1 


1 : 1.0 : 4.1 


1: 1.1:4.1 


1 : 1.2 : 4.1 


1 : 1.4 : 4.1 


1 : 1.6 : 4.0 


No. 4 to 2 in < 


3 " 4 


1 : 0.8 : 3.4 


1 : 0.9 : 3.4 


1 : 1.0 : 3.5 


1 : 1.1 : 3.4 


1 : 1.3 : 3.4 


6 " 7 


1 : 0.5 : 2.6 


1 : 0.6 : 2.6 


1 : 0.6 : 2.7 


1 : 0.7 : 2.6 


1 : 0.9 : 2.6 




8 "10 


1 : 0.2 : 1.6 


1 : 0.3 : 1.6 


1 : 0.3 : 1.7 


1 : 0.4 : 1.7 


1 : 0.4 : 1.7 


■ 


h to 1 


1 : 1.4 : 3.1 


1 : 1.5 : 3.0 


1 : 1.8 : 2.9 


1 : 2.1 : 2.8 


1 : 2.4 : 2.6 


1 to 1 in ' 


3 " 4 
6 " 7 


1 : 1.1 : 2.6 
1 : 0.8 : 2.0 


1 : 1.3 : 2.6 
1 : 0.8 : 2.0 


1 : 1.5 : 2.5 
1:1.0:1.9 


1 : 1.7 : 2.4 
1:1.1:1.9 


1 : 2.0 : 2.2 




1 : 1.3: 1.8 




8 "10 


1 : 0.4 : 1.2 


1 : 0.4 : 1.2 


1 : 0.5 : 1.2 


1:0.6: 1.2 


1 : 0.7 : 1.1 


c 


itol 


1 : 1.4 : 3.5 


1 : 1.5 : 3.4 


1 : 1.7 : 3.4 


1 : 2.0 : 3.3 


1 : 2.3 : 3.1 


1 to 1^ m I 


3 " 4 
6 " 7 


1 : 1.1 : 3.0 
1 : 0.6 : 2.2 


I : 1.2 : 2.9 
1 : 0.8 : 2.2 


1 : 1.4 : 2.9 
1 : 1.0: 2.2 


1: 1.6:2.8 
1 :1.1 :2.1 


1 : 1.9 ; 2.6 




1 : 1.3: 2.0 


. 


8 "10 


1 : 0.4 : 1.4 


1 : 0.4 : 1.4 


1 : 0.5 : 1.4 


1 : 0.6 : 1.3 


1 : 0.7 : 1.3 




Itol 


1 : 1.3 : 4.0 


1 : 1.4 : 4.0 


1 : 1.6 : 4.0 


1 : 1.9 : 3.9 


1 : 2.1 : 3.8 


^ to 2 in { 


3 " 4 


1 : 1.0 : 3.4 


1 : 1.2 : 3.4 


1 : 1.3 : 3.3 


1 : 1.5 : 3.3 


1 : 1.7 : 3.2 




6 " 7 


1 : 0.7 : 2.6 


1 : 0.8 : 2.5 


1 : 0.9 : 2.6 


1 : 1.0: 2.6 


1 : 1.1 : 2.5 




8 "10 


1 : 0.4 : 1.6 


1 : 0.4 : 1.6 


1 : 0.5 : 1.6 


1 : 0.5 : 1.6 


1 : 0.6 ; 1.6 




\ to 1 


1; 1.6:3.2 


1 : 1.8 : 3.2 


1 : 2.1 : 3.2 


1 : 2.4 : 3.1 


1 : 2.7 : 2.9 


\ to l| in 


3 " 4 
6 " 7 


1: 1.3:2.7 
1 : 0.9 : 2.0 


1 : 1.5 : 2.7 
1 : 1.0: 2.1 


1 : 1.7 : 2.7 
1:1.2:2.0 


1 : 2.0 : 2.6 
1:1.4:2.0 


1 : 2.3 : 2.5 




1 : 1.5: 1.8 


i 


8 "10 


1 : 0.5 : 1.2 


1 : 0.5 : 1.3 


1 : 0.6 : 1.3 


1 : 0.7 : 1.3 


1 : 0.8 : 1.2 




2 to 1 


1: 1.6:3.7 


1: 1.8:3.7 


1 : 2.0 : 3.7 


1 : 2.4 : 3.6 


1 : 2.6 : 3.5 


f to 2 in < 


3 " 4 
6 " 7 


1 : 1.3 : 3.1 
1 : 0.9 : 2.4 


1: 1.5:3.1 
1:1.1 :2.4 


I: 1.6:3.1 
1 :1.1 :2.4 


1 : 1.9 : 3.1 
1:1.3:2.4 


1 : 2.2 : 3.0 




1 : 1.5: 2.3 




8 "10 


1:0.5: 1.5 


1 : 0.5 : 1.5 


1 : 0.6 : 1.5 


1 : 0.7 : 1.5 


1 : 0.8 : 1.5 




itol 


1 : 1.6 : 4.2 


1 : 1.8 : 4.2 


1 : 2.0 : 4.2 


1 : 2.3 : 4.1 


1 : 2.6 : 4.0 


i to 3 in \ 


3 " 4 


1 : 1.3 : 3.5 


1: 1.5; 3.6 


1: 1.6=3.6 


1 : 1.9 : 3.6 


1:2,1:3.5 




6 " 7 


1 : 0.9 : 2.6 


1 : 1.0: 2.6 


1 : 1.1 : 2.6 


1 : 1.3: 2.6 


1:1.4:2.8 




8 "10 


1:05: 1.6 


1 : 0.5 : 1.6 


1 :0.fi: 1.7 


1 : 0.7 : 1.7 


1 : 0.8 : 1.7 



APPENDIX I. 

STANDARD NOTATION. 

All symbols used in the Tentative Specifications for Concrete and 
Reinforced Concrete have been collected here for convenience of refer- 
ence. The symbols are in general defined in the text near the point 
where formulas occur. In a few instances the same symbol is used in 
two distinct senses; however, there is little danger of confusion from 
this source. 

a = spacing of web reinforcement bars measured perpendicular 
to their direction (see Section 135); 

a = width of face of column or pedestal; 

a = angle between incKned web bars and longitudinal bars ; 

A = total net area of column, footing, or pedestal, exclusive of 
fireproofing; 

A' = loaded area of pedestal, pier or footing; 

A^ = A{\— p) =net area of concrete core of column; 

A'c = net area of concrete in columns (total column area minus 
steel area) ; 

As = effective cross-sectional area of metal reinforcement in ten- 
sion in beams or compression in columns; and the effect- 
ive cross-sectional area of metal leinforcement which 
crosses any of the principal design sections of a flat 
slab and which meets the requirements of Section 156; 

A J, = total area of web reinforcement in tension within a distance 
of a (ai, a2, ai, etc.) or the total area of all bars bent up 
in any one plane; 

h = width of rectangular beam or width of flange of T-beam; 

b' = width of stem of T-beam; 

^1 = dimension of the dropped panel of a flat slab in the direc- 
tion parallel to h;^ 

c = base diameter of the largest right circular cone which lies 
entirely within the column (including the capital) w^hose 
vertex angle is 90 deg. and whose base is l| in. below 
the bottom of the slab or the bottom of the dropped 
panel (see Fig. 14); 

1 In flat slab design, the column strip and the middle strip to be used when considering moments 
in the direction of the dimension / are located and dimensioned as shown in Fig. 15. The dimension li 
does not always represent the short length of the panel. When moments in the direction of the shorter 
panel length are considered, the dimensions / and /i are to be interchanged and strips corresponding to 
those shown in Fig. 15 but extending in the direction of the shorter panel length are to be considered. 

(65) 



66 Progress Report or Joint Committee 

c = projection of footing from face of column; 

C = total compressive stress in concrete; 

C = total compressive stress in reinforcement; 

d = depth from compression surface of beam or slab to center 
of longitudinal tension reinforcement; 

d^ = depth from compression surface of beam or slab to center 
of compression reinforcement; 

Ec = modulus of elasticity of concrete in compression; 

Es = modulus of elasticity of steel in tension = 30,000,000 lb. 
per sq. in.; 

fc = compressive unit stress in extreme fiber of concrete ; 

fc = ultimate compressive strength of concrete at age of 28 days, 
based on tests of 6 by 12-in. or 8 by 16-in. cylinders made 
and tested in accordance with the Standard Methods of 
Making and Storing Specimens of Concrete in the Field 
(Appendix 14) and the Tentative Methods of Making 
Compression Tests of Concrete (Appendix 13); 

/,. = compressive unit stress in metal core; 

f, = tensile unit stress in longitudinal reinforcement; 

fs = compressive unit stress in longitudinal reinforcement ; 

fjj = tensile unit stress in web reinforcement ; 

h = unsupported length of column; 

/ = moment of inertia of a section about the neutral axis for 
bending; 

j = ratio of lever arm of resisting couple to depth d; 

jd = d — z = arm of resisting couple ; 

k = ratio of depth of neutral axis to depth a; 

I ' = span length of beam or slab (generally distance from center 
to center of supports; for special cases, see Sections 108 
and 148); 

/ = span length of fiat slab, center to center of columns, in the 
rectangular direction in which moments are con- 
sidered;^ 

/i = span length of fiat slab, center to center of columns, per- 
pendicular to the rectangular direction in which mo- 
ments are considered;^ 

M = bending moment or moment of resistance in general; 

Mq = sum of positive and negative bending moments in either 
rectangular direction, at the principal design sections of 
a panel of a flat slab ; 

n — Es/Ec = ratio of modulus of elasticity of steel to that of 
concrete ; 



* See footnote, p. 65. 



On Concretk and Reinfc^rc^kd Concrete. 67 

= perimeter of bar; 

^0 = sum of perimeters of bars in one set; 

p = ratio of effective area of tension reinforcement to effective 
area of concrete in beams = /I ^/M; and the ratio of 
effective area of longitudinal reinforcement to the area 
of the concrete core in columns; 

p' == ratio of effective area of compression reinforcement to 
effective area of concrete in beams; 

P = total safe axial load on column whose h/R is less than 40 ; 

P' = total safe axial load on long column; 

r = ratio of cross-sectional area of negative reinforcement 
which crosses entirely over the column capital of a fiat 
slab or over the dropped panel, to the total cross- 
sectional area of the negative reinforcement in the two 
column strips; 

r„ = permissible working stress in concrete over the loaded area 
of a pedestal, pier or footing; 

R = ratio of positive or negative moment in two column strips 
or one middle strip of a flat slab,. to AIo; 

R = least radius of gyration of a section; 

s = spacing of web members, measured at the neutral axis and 
in the direction of the longitudinal axis of the beam; 

/ = thickness of flange of T-beam; 

/i = thickness of flat slab without dropped panels or thickness 
of a dropped panel (see Fig. 14); 

ti = thickness of flat slab with dropped panels at points away 
from the dropped panel (see Fig 14); 

T = total tensile stress in longitudinal reinforcement; 

u = bond stress per unit of area of surface of bar; 

V = shearing unit stress; 

V = total shear; 

V = external shear on any section after deducting that carried 

by the concrete; 

w = uniformly distributed load per unit of length of beam or 
slab; 

w = upward reaction per unit of area of base of footing; 

w' = uniformly distributed dead and Kve load per unit of area 
of a floor or roof; 

W = total dead and live load uniformly distributed over a 
single panel area; 

2 = depth from compression surface of beam or slab to result- 
ant of compressive stresses. 



APPENDIX II. 



See Appendix I for explanation of symbols ttsed in figures. 

fc 




Fig. 1. — Nomenclature for Concrete Beam Reinforced for Tension. 

fc 




X 



A ^__A> 



kd 




Fig, 2. — Nomenclature for Concrete Beam Reinforced for Tension and Compression. 




Fig. 3. — Nomenclature for Reinforced Concrete T-Beam. 
(68) 



On Concrete and Reineorced Concrete. 



69 



.--4-- 



<: '— 



S 



^ Allowable 6hear = 0. 02 fc 



Fig. 4. — Typical Reinforced Concrete Beam; Principal Longitudinal Bars not 

Anchored. 



m 



Allowable Shear = 0.03 fc 



Fig. 5. — Typical Reinforced Concrete Beam; Principal Longitudinal Bars Anchored. 



^ 



^ 






Series of 
VerNca I Siirrups . 



Series of 
Inclined Bars 
orSfirrups. 



Fig. 6. — Typical Reinforced Concrete Beam; Web Reinforced by Means of Series 
of Vertical Stirrups or Series of Inclined Bars or Stirrups. 



-Not less than 20l, 






^/. 'C>-.i 



'■^f.f. 



kU 



m 



Bars Bent up 
in Single Plane . 



Fig. 7. — Typical Reinforced Concrete Beam; Principal Longitudinal Bars Bent up 

in Single Plane. 



70 



Progress Report of Joint Committee 




Fig. 8. — Typical Reinforced Concrete Beam with Anchored Longitiidinal Bars and 

Vertical Stirrups. 




Spacing al deiermined by Shear 

on SecHon J . 



Fir,. 9. — Typical Beam with Web Reinforced by Means of Series of Inclined Bars. 



On Concrete and Reinforced Concrete. 



71 



[<""'•• K must not exceed 
0.02 fcon this Sec f ion. 




Section of Inclined Bars 
Delermined by Maximum 
Shear al Edcfe of Support 

Fig. 10.— Typical Beam with Web Reinforced by Means of Bars Bent up in Single 

Plane. 



.-•■Po in fs of In fie c iio n 



"1 



.i.j_CjJCwI__l. 



-, — r-nrri--- 
I I ,1 I ' I I 
I >i^ I ' ' ' 

._L._l_iL_l_J.J_L. 



k- 



...j^^' Assumed Tension in Bottom-''' \ - 
I Bar at these Points equals \ 
~ of Tension at Section of 
Maximum Moment. 

This Length determined byAnchorage 

in Bond or by Mechanical Anchorage . 



Fig. 1 1 . — Typical Web Reinforcement for Continuous Beams. 



p ^ 




rnB-« 




PI 


IUaJ 


.5 

c5 


!=*J 


3.: 


kJ 




00 












.Cn 



OJ 



.•-•-0. 



^SDiam. 



Fig. 12. — Typical Methods of Anchoring Vertical Stirrups. 




nnn 

DDD 



DDD 
DDD 



• • 



DDD 

DDD 




Fig. 13. — Typical Reinforced Concrete Beam-and-Tile Construction. 



72 



Progress Report of Joint Committee 



!<• 



^^ 



Vyf^, 



'% 



Vf/U,-r.. 



z 



.i. — 






Criiical 
Sections 
for Shear. 



Pig. 14. — Typical Column Capital and Sections of Flat Slab with Dropped Panel. 



• Sections of Cn'Hcal 
Negative Moment — -. 



^ 



-+- 



2 

I ^ s> 
I ^ ^ 

■Sections of Critical 



t 






Positive Morhent-'-' %■ 



1 N. 



The Span Lengths I and If 
are interchangeable 
according to the Direction 
of the /foment under 
Cons id era tion 



Fig. 15. — Principal Design Sections of a Flat Slab. 



On Concrete and Reinforced Concrete. 



73 




1 

i >/i 

j / \ 


>1<- a -^ 
1 1 


/ 1 

y 1 

L 

1 

1 
1 

r 

X 1 
'X • 

i\ 1 

X 1 


h 


<.— c - 



(a) 
Plan, 




. Critical Section 
for Diagonal 
Tension in Pile 
Footings 



[J U U LJ U Ui 



h- 



L ■ 

Elevation. 



Fig. 16. — Typical Sloped Reinforced 
Concrete Footing on Piles. 




Fig. 17.— Typical Sloped Reinforced 
Concrete Footing on Soil. 




Fig. 18.— Typical Sloped or Stepped Footing. 



LIBRARY OF CONGRESS 



020 366 042 n 4 



LIBRARY OF CONGRESS ^ 

020 366 042 A 



Hollinger 

pH S5 

Mfll Run F03-2193 



